Add twitter service.
Merge branch 'master' of https://github.com/krzysztof-trzepla/tai2014
Add user connection.
Merge branch 'master' of https://github.com/krzysztof-trzepla/tai2014

Conflicts:
	src/main/java/pl/edu/agh/student/model/Event.java
	src/main/java/pl/edu/agh/student/model/Tweet.java