fix the opaque property of main window after exiting full screen mode
Fix the top/bottom strips when entering full screen mode
Oops, fix a crash bug.
Merge branch 'master' into 10.7-full-screen
Deal the case when ratioH < ratioW

Besides, change the setFont: method. Now the original size parameters
are stored when entering fullscreen/presentation, and restored when
exiting. This should prevent ruining shape by repeating enter/exit
fullscreen.