Merge pull request #36 from xsacha/master

Build fix for Symbian, Blackberry10, Harmattan, Pandora
Add dither to state. Allow choosing FBO color depth. Disable VBO for draw_buffer but keep code.
Routing loggings in Symbian though qDebug to the console
Merge pull request #37 from Summeli/master

routing logs though qDebug in Symbian
tab key for turbo mode
Merge pull request #38 from KentuckyCompass/tab_turbo

tab key for turbo mode