Default android.sdk setting causes sensor rotate on Android to fail

[brousch]

The default android.sdk setting of 21 causes sensor-based rotatation to fail on Android due to python-for-android issue kivy/python-for-android#148

Ideally, we should fix this by fixing the py4a issue.

Right now you cannot work around this issue because buildozer uses the android.sdk option to both determine which SDK to download and use to compile and to determine what gets sent to py4a's build.py as the --sdk value. These two things should be separated so that you can compile with one SDK (21) but target another (12). More information about this topic can be found at http://developer.android.com/guide/topics/manifest/uses-sdk-element.html

[tito]

Latest python-for-android should fix this one. Check kivy/python-for-android#148 for the commit

[brousch]

Fixed by #148