CleanUp and Use a global random number generator
CleanUp
Add a unit test of block
Comments
Repair and Add pause

pause实现可以参考MainWindow的Controller
Add user Api to system
Repair ScoreSystem
Comments
Merge remote-tracking branch 'origin/AdvancedGUI' into gamelogic

Conflicts:
	Tetris/Block.cs
	Tetris/TetrisGame.cs
Repair Merge Bugs
Repair Bugs
Some changes

Change the text of dialog, repair the next block, refine the drawevent
Stop Engine when exit program
Fixed Inverse Control and refactor the draw method
Performance Hack
Add Fps display
Move RoundTicks to Settings
add SetInversed
Merge remote-tracking branch 'origin/master' into PlayerController
Fix bugs

Improve the speed of display the next block, make controller receive the
esc first, change the ai of reverse gun(fall directly)