Initial gradle support

* compiling works
* instrumentTest currently only uses the catroidTest module
Libgdx native extensions are now included & Android Studio import works
Merged catroidUiTest project into catroidTest
Moved gdx native jar because eclipse doesn't like it
Added sdk version to gradle
removed catroidUiTest from source tests
catroidSourceTest now builds with gradle
Added Polidea TestRunner
Using older version of build tools until jenkins is updated
Added jenkins task for package renaming to build.gradle
Merge branch 'master' into gradle

Conflicts:
	catroidUiTest/AndroidManifest.xml
Added build code parameter support to build.gradle
Now setting the package name in build.gradle so it doesn't get messed up when renaming package
Added git describe to build config
Fixed ProjectUpAndDownloadTest
Gradle hack to get the mock activities into the test manifest
fixes the gradle hack to get the mock activities into the test manifest
Fixed ProjectTest
Merge branch 'master' into gradle
Fixed ProjectManagerTest