[android] some modifications
[android] connections reimplemented
Merge branch 'android-client-safe-wrappers'
Merge branch 'android-client-connection'

Conflicts:
	android/src/pl/killerapps/academia/activities/ConnectActivity.java
	android/src/pl/killerapps/academia/activities/pad/PadActivity.java
	android/src/pl/killerapps/academia/activities/subject/AktivityActivity.java
	android/src/pl/killerapps/academia/activities/subject/SubjectsActivity.java