Updated project files

Signed-off-by: Oscar Cardoso <darkson.xd@gmail.com>
Started the implementation of the database subsystem by vogella.com

Signed-off-by: Oscar Cardoso <darkson.xd@gmail.com>
Added layout properties for the ArrayList of check events.

Resized check button height.
Added hello world string.
Changed accesibility to CHECK_IN and CHECK_OUT final Strings in Event.java.
Correct parsing of time in toString().
EventDataSource fixed compilation problems.
Use proper app tag for MySQLiteHelper logs.
Add imports for list.
Changed parent class of MainActivity to ListActivity.
Implemented onClick, onResume and onPause events.