align4, AI review
updated AI
backup sync
fixed bugs in align4-single player and added reload bar button
align4, replaced mode as string by twoPlayer as a bool

Makes the code simpler
align4, moved scores in the bar to make room for the game area
align4, minor moved a set of property to ease readability
align4, major rework to remove hardcoded coordinates

Use a grid instead of a GidLayout to let us force the column numbers.
All the code has beenn adapted to get the coord of the cells instead of
being hardcoded.
Added horizontal anim of the falling piece.
Merge branch 'brat.197/gcompris-align4-singleplayerMOD'