Use transitive dependencies.

The technique of referencing Android libraries via an "@aar" suffix prevented transitive dependencies from being used correctly.  This change fixes that issue.

Files changed:

BasicAISWebViewSampleApp/build.gradle
BasicBundledVideoSampleApp/build.gradle
BasicFreeWheelSampleApp/build.gradle
BasicOmnitureSampleApp/build.gradle
WebVTTSampleApp/build.gradle
build.gradle
    * Remove the "@aar" suffix on Android library dependency references.

BasicOnceUxSampleApp/src/main/java/com/brightcove/player/samples/onceux/basic/MainActivity.java
    * Use the simplified interface for setting up the ad server and content server URL references.

gradle/wrapper/gradle-wrapper.properties
    * Allow Android Studio to access Gradle sources.