Added registration API and password registration helper method
Added updateAvatarUrl helper method
Added the presence API interface
Added license information
Merge branch 'master' of https://github.com/matrix-org/matrix-android-sdk

Conflicts:
	sdk/src/main/java/org/matrix/androidsdk/data/Room.java
Added the rooms API
Merge branch 'master' of https://github.com/matrix-org/matrix-android-sdk
Adding rooms API calls from the the main API client object
Added constants