TODO
====

Common
------

     DONE  common usable status line in display.cpp
     DONE  fix drawing code, when frame is off
           precise timing of main loop on different hardware
           help screen (README browser)
           add game specific settings
           remember gamestate, when quitting game
           implement (hardware like) sprite engine
           more games (pacman, breakout, space invaders, ...)
           saved highscore list
           i18n support
           use pthread_cond_* for keys


Tetris
------

           prevent rising pieces, by fast rotation


Tron
----

     DONE  fix pixel errors


Minesweeper
-----------

           switch icon drawing code to make use of Bitmap class