ob_end_flush() HTTP header conflict

Apparently ob_end_flush disallows any further http headers, moved to be
called just before readfile()
An absolute ton of GeSHi libraries
Re-adding GeSHi support under handlers
Resolve handler termination bug
QRlib removal

QRlib has proven to be outdated and buggy, caching of QR codes was not
functioning as intended
Hopefully fix caching directory typos
Change over QR to use Google API