Added ActionbarSherlock to support Android >2.3.3

	Actionbarsherlock must be in ../ActionBarSherlock/library
Fixed bug that prevented onContextItemSelected calls.
New Project is now an action item.
Added warning message when starting no project!

	If the user tries to start a pomodoro without having
	selected a project the pomodoro won't be started and
	a message will be displayed.