Add Cocoa Touch Static Libraries documentation.

Author: e2l3n

PLUGINS.md

@@ -99,12 +99,16 @@ my-plugin/
     │   └── AndroidManifest.xml
     └── ios/
         ├── MyiOSLibrary.framework
-        └── Info.plist
+        ├── Info.plist
+        ├── MyStaticiOSLibrary.a
+        └── include/
+            └── MyStaticiOSLibrary/
+                └── ...
 ```
 
 * `platforms\android`: This directory contains any native Android libraries packaged as `*.jar` and `*.aar` packages. These native libraries can reside in the root of this directory or in a user-created sub-directory. During the plugin installation, the NativeScript CLI will configure the Android project in `platforms\android` to work with the plugin. 
 * `platforms\android\res`:  (Optional) This directory contains resources declared by the `AndroidManifest.xml` file. You can look at the folder structure [here](http://developer.android.com/guide/topics/resources/providing-resources.html#ResourceTypes).
-* `platforms\ios`: This directory contains native iOS frameworks (both static and shared). During the plugin installation, the NativeScript CLI will copy these files to `lib\iOS` in your project and will configure the iOS project in `platforms\ios` to work with the frameworks.
+* `platforms\ios`: This directory contains native dynamic iOS Cocoa Touch Frameworks (`.framework`) and Cocoa Touch Static Libraries (`.a`). During the plugin installation, the NativeScript CLI will copy these files to `lib\iOS` in your project and will configure the iOS project in `platforms\ios` to work with the libraries. In case the plugin contains a Cocoa Touch Static Library (`.a`), you must place all public headers (`.h`) under `include\<Static Library Name>\`. Make sure that the static libraries are built at least for the following processor architectures - armv7, arm64, i386.
 * `platforms\android\include.gradle`: This file modifies the native Android configuration of your NativeScript project such as native dependencies, build types and configurations. For more information about the format of `include.gradle`, see [include.gradle file](#includegradle-specification).
 
 ### Package.json Specification