Updating to Android Studio 0.4.0, Gradle 1.9

Android Studio 0.4.0 requires Gradle 1.9, which requires the Android
wrapper 0.7+, and 0.7.1 adds a bug fix that eliminates duplicate files.
Merge pull request #93 from OneBusAway/NewGradleFixes

Updating to Android Studio 0.4.0, Gradle 1.9