Final task of the 128x64dots GLCD implementation

This is the final task of the GLCD implementation.
It adds the necessary code for the visualisation of main screen, menues, welcome graphics etc. It adds the u8glib (https://code.google.com/p/u8glib/) to the addons.

Code was tested with the following hardware: http://www.reprap.org/wiki/STB_Electronics

--> see pull request #411 (already commited)
--> see pull request #408 (already commited)
--> see pull request #399 which contains all necessary changes in one request.