Spring Security refactoring.
Authentication is reloaded from session manually instead of using filterchain.
Renamed implementation of application servlet into IntlibApplicationServlet.
Removed unnecessary code from push handler.
Refactoring of the push handler.
Merge branch 'ssec'

Conflicts:
	frontend/src/main/java/cz/cuni/xrg/intlib/frontend/AppEntry.java
	frontend/src/main/java/cz/cuni/xrg/intlib/frontend/gui/views/Login.java