Draw flat pieces
Improve games descriptions
Improve style on scores window
Show in the user color the last game played in the scores window
Replace the combo to select the gmes by a palette with icons
Remove horizontal margin for the table, we don't use the border tiles anymore
Fix automatic player put two pieces after request more pieces
Add cairo context save/resore
Implement a AUTO mode, useful to test

In this mode, the computer play against himself.
Chnages to use more screen state

In the XO, with the actual pieces size, there are not
too much space to put the pieces.
The previous strategy required not use the tiles in the border of the board
That is too much space wasted.
To try to make a better use, changed the algorithm
to put pieces until the border of the board
and show the pieces of the automati player (flipped) smaller.
Fix control of end of game

In the case of two players passing, the variable player
was overwriten and had wrong results
Use random to balance what ends try first
Adjust bottom margin
Move up the 'User pass' message
Improve control of free spaces to reduce probability of join wrong pieces
Implement end of game messages designed by Dan
New wood image for the background