fix travis
Merge pull request #54 from Diolor/master

Fix travis ci
Update Gradle wrapper to 2.1
Update Android Gradle plug-in to 0.13.3
Create about_libraries_def.xml

Allows AboutLibraries (https://github.com/mikepenz/AboutLibraries) to autodetect the usage of this library and show it on a dialog.
Merge branch 'update-gradle' of https://github.com/friederbluemle/SmoothProgressBar into dev
Incremented version name for library-circular
Merge remote-tracking branch 'upstream/dev' into dev