Merge pull request #69 from bartkiers/maven-pom

Added a Maven pom.xml
Upped android-maven-plugin version

Upped the `android-maven-plugin` from 3.1.1 to 3.6.1. The older version does not play well with the later Android SDKs (level 17+).
Merge pull request #72 from bartkiers/patch-1

Upped android-maven-plugin version