chore(CONTRIBUTING): merge relevant updates from Angular.js

Port changes to Angular.js CONTRIBUTING.md since AngularDart version
was forked.

Closes #748

Author: chalin

CONTRIBUTING.md

@@ -6,22 +6,31 @@ place to start if you are interested in contributing to AngularDart.
 We'd love for you to contribute to our source code and to make AngularDart even better than it is
 today! Here are the guidelines we'd like you to follow:
 
-## Code of Conduct
+ - [Code of Conduct](#coc)
+ - [Question or Problem?](#question)
+ - [Issues and Bugs](#issue)
+ - [Feature Requests](#feature)
+ - [Submission Guidelines](#submit)
+ - [Coding Rules](#rules)
+ - [Commit Message Guidelines](#commit)
+ - [Signing the CLA](#cla)
+
+## <a name="coc"></a> Code of Conduct
 Help us keep Angular open and inclusive. Please read and follow our [Code of Conduct][coc].
 
-## Got a Question or Problem?
+## <a name="question"></a> Got a Question or Problem?
 
 If you have questions about how to use AngularDart, please direct these to the [Google Group][groups]
 discussion list or [StackOverflow][stackoverflow].
 
-## Found an Issue?
+## <a name="issue"></a> Found an Issue?
 If you find a bug in the source code or a mistake in the documentation, you can help us by
 submitting and issue to our [GitHub Repository][github]. Even better you can submit a Pull Request
 with a fix.
 
 **Please see the Submission Guidelines below**.
 
-## Want a Feature?
+## <a name="feature"></a> Want a Feature?
 You can request a new feature by submitting an issue to our [GitHub Repository][github].  If you
 would like to implement a new feature then consider what kind of change it is:
 
@@ -34,7 +43,7 @@ project.
 * **Small Changes** can be crafted and submitted to [GitHub Repository][github] as a Pull Request.
 
 
-## Want a Doc Fix?
+## <a name="docs"></a> Want a Doc Fix?
 If you want to help improve the docs, it's a good idea to let others know what you're working on to
 minimize duplication of effort. Before starting, check out the issue queue.
 
@@ -45,7 +54,7 @@ For large fixes, please build and test the documentation before submitting the P
 accidentally introduced any layout or formatting issues. You should also make sure that your commit message
 is labeled "docs:" and follows the **Git Commit Guidelines** outlined below.
 
-## Submission Guidelines
+## <a name="submit"></a> Submission Guidelines
 
 ### Submitting an Issue
 Before you submit your issue search the archive, maybe your question was already answered.
@@ -69,7 +78,7 @@ chances of your issue being dealt with quickly:
 ### Submitting a Pull Request
 Before you submit your pull request consider the following guidelines:
 
-* Search [GitHub][github] for an open or closed Pull Request
+* Search [GitHub](https://github.com/angular/angular.dart/pulls) for an open or closed Pull Request
   that relates to your submission. You don't want to duplicate effort.
 * Please sign our [Contributor License Agreement (CLA)](#signing-the-cla) before sending pull
   requests. We cannot accept code without this.
@@ -81,7 +90,7 @@ Before you submit your pull request consider the following guidelines:
 
 * Create your patch, **including appropriate test cases**.
 * Follow our [Coding Rules](#coding-rules).
-* Run the full AngularDart test suite, as described in the [developer documentation][dev-doc],
+* Run the full Angular test suite, as described in the [developer documentation][dev-doc],
   and ensure that all tests pass.
 * Commit your changes using a descriptive commit message that follows our
   [commit message conventions](#commit-message-format) and passes our commit message presubmit hook
@@ -92,6 +101,7 @@ Before you submit your pull request consider the following guidelines:
      git commit -a
      ```
   Note: the optional commit `-a` command line option will automatically "add" and "rm" edited files.
+
 * Push your branch to GitHub:
 
     ```shell
@@ -140,15 +150,15 @@ from the main (upstream) repository:
     git pull --ff upstream master
     ```
 
-## Coding Rules
+## <a name="rules"></a> Coding Rules
 To ensure consistency throughout the source code, keep these rules in mind as you are working:
 
   * All features or bug fixes **must be tested** by one or more [specs][unit-testing].
   * All public API methods **must be documented** with [doc comments][doc-comments].
   * With the exceptions listed below, we follow the rules contained in
   [Google's Dart Style Guide][dart-style-guide].
 
-## Git Commit Guidelines
+## <a name="commit"></a> Git Commit Guidelines
 
 We have very precise rules over how our git commit messages can be formatted.  This leads to **more
 readable messages** that are easy to follow when looking through the **project history**.  But also,
@@ -205,7 +215,7 @@ reference GitHub issues that this commit **Closes**.
 
 A detailed explanation can be found in this [document][commit-message-format].
 
-## Signing the CLA
+## <a name="cla"></a> Signing the CLA 
 
 Please sign our Contributor License Agreement (CLA) before sending pull requests. For any code
 changes to be accepted, the CLA must be signed. It's a quick process, we promise!
@@ -215,16 +225,16 @@ changes to be accepted, the CLA must be signed. It's a quick process, we promise
   [print, sign and one of scan+email, fax or mail the form][corporate-cla].
 
 
-[groups]: https://groups.google.com/forum/#!forum/angular-dart
-[stackoverflow]: http://stackoverflow.com/questions/tagged/angular.dart
-[github]: https://github.com/angular/angular.dart
-[runnable]: http://runnable.com/
-[unit-testing]: https://www.dartlang.org/articles/dart-unit-tests/
-[doc-comments]: https://www.dartlang.org/articles/doc-comment-guidelines/
-[dart-style-guide]: https://www.dartlang.org/articles/idiomatic-dart/
-[individual-cla]: http://code.google.com/legal/individual-cla-v1.0.html
-[corporate-cla]: http://code.google.com/legal/corporate-cla-v1.0.html
+[coc]: https://github.com/angular/code-of-conduct/blob/master/CODE_OF_CONDUCT.md
 [commit-message-format]: https://docs.google.com/document/d/1QrDFcIiPjSLDn3EL15IJygNPiHORgU1_OOAqWjiDU5Y/edit#
 [communityMilestone]: https://github.com/angular/angular.dart/issues?milestone=13&state=open
-[coc]: https://github.com/angular/code-of-conduct/blob/master/CODE_OF_CONDUCT.md
+[corporate-cla]: http://code.google.com/legal/corporate-cla-v1.0.html
+[dart-style-guide]: https://www.dartlang.org/articles/idiomatic-dart/
 [dev-doc]: https://github.com/angular/angular.dart/blob/master/DEVELOPER.md
+[doc-comments]: https://www.dartlang.org/articles/doc-comment-guidelines/
+[github]: https://github.com/angular/angular.dart
+[groups]: https://groups.google.com/forum/#!forum/angular-dart
+[individual-cla]: http://code.google.com/legal/individual-cla-v1.0.html
+[runnable]: http://runnable.com/
+[stackoverflow]: http://stackoverflow.com/questions/tagged/angular.dart
+[unit-testing]: https://www.dartlang.org/articles/dart-unit-tests/