Android: update API levels for building

Android: update API levels for building

Build all components against API level 22 (Android 5.1). Decrement
minSdkVersion, because ORTE needs pthread_rwlock_* and these are provided
since API level 9 (Android 2.3).

This is the recommended setting by Google. By saying to target the latest
API, we prevent invoking compatibility behaviors. These behaviors are
sometimes buggy (during testing with 'shape_android' after interacting with
menu items they were duplicated each time I tapped on them).

By saying that minimum API level is 9 we declare, that jORTE does not
require any features of the later APIs and that it runs without any
problems at that level.

I tested 'shape_android' on Android 2.3/4.0/4.1/4.3/4.4/5/5.1.