Upgrade dependencies, make work with Android Studio 1.0

com.android.tools.build:gradle 0.12.+ -> 1.0.0
com.jakewharton.sdkmanager:gradle-plugin 0.10.+ -> 0.12.0
org.robolectric:robolectric-gradle-plugin 0.12.+ -> 0.14.1

runProguard -> minifyEnabled

Gradle wrapper "1.12-all" -> "2.2-all"