[GB/CGB] Gambatte 0.5.0 wip2

Rough changelog since wip1:

• XvBlitter: Try grabbing all adapter ports before giving up. Fixes XVideo engine unnecessarily unavailable while mplayer running.
• Don't call glTexSubImage2D in blit() because that tends to block on OS X (and quite possibly other implementations), use paged-flipped sw double buffer.  This should fix OS X being less audio underrun-resistant than other platforms.
• Add GBC DMG palettes. Wasn't able to use the .pal-files by nitro322, but  thanks nonetheless.
• Use mapped GBC palette by default for recognized DMG game titles.  libgambatte: Add ROM title getter.
• Add Turbo A/B input mapping with configurable number of frames per press.
• Add Quit input mapping.
• Support Game Genie codes.
• Support 01xxxxxx Game Shark codes.
• Support .gz files.
• Avoid using magic header values to detect file type to avoid potential conflicts  with ROM content.
• Gambatte Qt: Support command line parameters.
• Gambatte Qt: Work around WMs messing up if full screen is set too early.
• InputDialog: Protect against Qt signaling redundant inputbox focusIn events causing joystick mutex relock, which could basically break joystick input.
• Always pause on file dialog for all platforms. Too much screwiness with the way native dialogs work in Qt, and I think this may be overall nicer either   way.
•  AlsaEngine: Limit number of iterations of snd_pcm_writei loop to make sure we  don't get an infinite loop in weird cases.
• Allow loading HuC1 ROM images.
• Provide option to use heuristics to support certain multicart MBCs disguised as MBC1 (Bomberman Collection, Mortal Combat I & II, Super Chinese Land 1,2,3 Dash,  maybe others)
• Default fast-forward speed 8.
• libgambatte: compilation and warning fixes for clang.
• Better facilitate overriding CC and CXX from the command line.
• Mac OS X build fixes for newer SDKs.
• Redirect some error printing from stdout to stderr
• Minor fixes, refactoring and clean-ups.