Add maven-integration

Then simply run `maven clean package` to generate the apk.

Need extra dependency to artifact android.support:compatibility-v4:11
because of usage of SparseArrayCompat (official
com.google.android:support-v4:11 is not available in the central naven
repository). To get this dependency, use the github project
maven-android-sdk-deployer
(https://github.com/mosabua/maven-android-sdk-deployer).
Merge pull request #17 from tbruyelle/maven-integration

Add maven-integration