Updated all pom files to support AAR's instead of apklib

As per issue #55 updating the android-maven-plugin to 3.8.2 now supports packaging and consuming aar formats. The documentation on the format can be found here http://tools.android.com/tech-docs/new-build-system/aar-format. Tested packaging both the library and sample and with the latest plugin it consumes the aar and the sample compiles just fine.