Merge pull request #1 from xpgdk/master

Prepare aware for multiple backends:
Merge pull request #2 from xpgdk/master

Add aware::factory
Add initial version of Java / Android Aware.

Still alot of rough edges
Cleanup of aware::android
Add run_android_test target, which runs a small test application
Add first implementation of aware::android::announce_socket
Cleanup of aware::android and make use of aware::contact and AwareContact in all steps of monitoring