Android Studio Fixes

Using Android Studio 0.5.7, the samples should build successfully again.

BasicAISWebViewSampleApp/build.gradle
BasicAdobePassWebViewSampleApp/build.gradle
BasicOnceUxSampleApp/build.gradle

  * Moved dependencies down into the root build.gradle.

BasicCastSampleApp/build.gradle

  * Bumped the buildToolsVersion up to 19.0.3.

README.md

  * Add descriptions for the missing samples.

build.gradle

  * Bumped the gradle build tools version up to 0.9.+.

  * Bumped the Google IMA version up to beta 6.

  * Bumped the buildToolsVersion up to 19.0.3.

  * Added dependency configuration for AdobePass, AIS, and OnceUX subprojects.

gradle.properties

  * Removed the run*SampleApp flags as these were causing Android
    Studio issues.

gradle/wrapper/gradle-wrapper.properties

  * Bumped the gradle version up to 1.11.

settings.gradle

  * Removed the conditional logic and commented out the projects that
    have unsatisfied dependencies out of the box.  This helped to make
    Android Studio happy again.