frontend: change how exit is done

will no longer be done from recompiler callback that could cause
still used data to be freed
frontend: do all bpp handling in plugin_lib
attempt to make gles plugin work under RPi
disable standalone pluign builds

these were for testing mostly, not for general use.
Also fix a typo along the way.
frontend: check for xlib when it's needed
move cspace back to frontend

plugins no longer depend on it
frontend: add armv6 color space converter
Merge git://github.com/notaz/pcsx_rearmed