fix(ngTouch): remove ngClick override and $touchProvider.ngClickOverrideEnabled()

Closes angular#15755

BREAKING CHANGE:

The `ngClick` directive from the ngTouch module has been removed, and with the also the
corresponding $touchProvider.ngClickOverrideEnabled() method.

If you have included ngTouch in your application with a version of 1.5.0 or higher, and have not
changed the value of $touchProvider.ngClickOverrideEnabled()`, then there are no migration steps.

The `ngClick` override directive had been deprecated and by default disabled since v1.5.0,
because of buggy behavior in edge cases, and a general trend to avoid special touch based
overrides of click events. If you still need a touch override, consider using
[Fastclick](https://github.com/ftlabs/fastclick).

Note that the `$touch` service still offers the `ngClickOverrideEnabled()` function for
libraries that want to detect if an app uses the click override. Starting with 1.7.0, it
will always return `false`.

Author: Narretz

angularFiles.js

@@ -146,7 +146,6 @@ var angularFiles = {
     'ngTouch': [
       'src/ngTouch/touch.js',
       'src/ngTouch/swipe.js',
-      'src/ngTouch/directive/ngClick.js',
       'src/ngTouch/directive/ngSwipe.js'
     ],
     'ngAria': [

docs/content/misc/downloading.ngdoc

@@ -111,7 +111,7 @@ The set of files included in each version directory are:
   * __`angular-route.js`__ — Routing and deep-linking services and directives for AngularJS apps.
       ({@link module:ngRoute API docs})
   * __`angular-sanitize.js`__ — Functionality to sanitize HTML. ({@link module:ngSanitize API docs})
-  * __`angular-touch.js`__ — Touch events and other helpers for touch-enabled devices.
+  * __`angular-touch.js`__ — Touch events for touch-enabled devices.
     ({@link module:ngTouch API docs})