Update build tools to v.19.1.0.
Update Gradle plug-in to v.0.9.+.
Set 'compileSdkVersion' to v.19.
Update Gradle plug-in to v.0.10.+.

+ Running `./gradlew install` only works when
  https://github.com/novoda/robolectric-plugin/pull/17
  is deployed to MavenLocal!
Update Gradle plug-in to v.0.11.+.
Update Gradle wrapper to v.1.12.
Update tests and build scripts. Add Travis
Merge branch 'MariusVolkhart/tests' into feature/update-project
Merge branch 'feature/update-project'
Add Travis build status badge.
Add contributors.
Add Maven central badge.
Modify the preferences asynchronously