Update Gradle to 2.0 + plugin updates

(cherry picked from commit cfc7f236205daebb0db24518d96b61d89ad229aa)
Update dependencies
Wrapper related change
Update code quality check tools to the latest versions
Add jcenter() Maven repository
Add Travis.CI support
Merge branch 'multi-project' to update code quality tools and to support
Travis.CI

Conflicts:
	gradle/wrapper/gradle-wrapper.properties