Merge branch 'gradle-android-3.4' into 'master'

.idea/codeStyles/Project.xml

bramble-android/build.gradle

bramble-android/witness.gradle

bramble-api/build.gradle

bramble-api/witness.gradle

bramble-core/build.gradle

bramble-core/witness.gradle

bramble-java/build.gradle

bramble-java/witness.gradle

briar-android/build.gradle

briar-android/witness.gradle

briar-core/build.gradle

briar-core/witness.gradle

briar-headless/build.gradle

briar-headless/witness.gradle

build.gradle

gradle.properties

gradle/wrapper/gradle-wrapper.properties