Adds Wifi Direct capability to Android Unity3d builds

Provides a C# wrapper around the Wifi-Buddy project

Copy the Unity3d/Plugins folder into your Assets folder, and create a C# class that inherits from WifiDirectBase.cs

Doxygen files are hosted here

An example that uses Wifi-Direct to change the color of a cube is available here.

1. Directory ./Android is already a Android Studio Gradle project, just import it into Android Studio
2. Use the build button in the Android Studio menu bar (the gradle file has been pre-configured)
3. Go into the "app-debug.aar" file in the app/build/outputs/aar/ folder
4. Open the aar with 7zip and delete the "res" folder
5. Inside the aar delete the 'R.txt' file
6. Open "lib" folder in the aar and delete "unity.jar"
7. Copy the android-support-v4.jar file from the Android SDK install location into "libs" inside the aar
8. Copy the .aar into (your Unity3d project)/Assets/Plugins/Android and rename it "UnityWifiDirect.aar", and make sure WifiDirectBase.cs is inside Assets/Plugins
9. Folow the instructions in the "Using the Library" section above