Merge pull request #74 from marqs85/master

Update gamecon driver version
Reboot dialog after firmware update, enable SDL driver for RetroArch
Updated filename for themes download.
Enable/disable SNESDev on boot and configure RetroArch key mapping.
Added DGEN emulator, RetroArch video configuration, emulators folder, Wolfenstein3D engine, SNESDev menu refinement
Use "git pull" instead of recloning git repositories every time. Also trust make to only remake what is necessary.
Merge pull request #77 from chewi/master

Use "git pull" and trust make for rebuilding
Added supplementary folder, added make clean for ES
Bug fixes for installation of SNESDev and Emulation Station
Updated AUTHORS
Bug fix for SNESDev installation
Bug fix for SNESDev configuration
Updated binaries.
"make clean" is no longer necessary for EmulationStation.
Merge pull request #78 from chewi/master

"make clean" is no longer necessary for EmulationStation.
Fixed folder for ES-scraper
Modified GnGeo installation, fixed gitPullOrClone, fixed directory of RetroArch
Fixed ES-scraper folder check
Fixed MAME theme
Added installation of ca-certificates

Added installation of ca-certificates before installation rpi-update. This should enable the RetroPie script to work with RaspBMC (see also http://petrockblog.wordpress.com/2012/07/22/retropie-setup-an-initialization-script-for-retroarch-on-the-raspberry-pi/#comment-1208).