use canon firmware semaphore for IO access, should fix startup crashes and CFG not saving on dryos - from philmoz in http://chdk.setepontos.com/index.php?topic=6179.msg111459#msg111459
a2300: Fix camera_set_led(), and fix code_gen.txt svn properties
Fix for script parameters not always being saved correctly.
usb remote cleanup from waterwingz in http://chdk.setepontos.com/index.php?topic=650.msg111552#msg111552
Add SetHPTimerAfterNow and CancelHPTimer functions to stubs_entry.S
finsig_dryos: preliminary DryOS r54 support, better support for some r52 cameras (sx510 ATM)
a470 update: port rewritten using code_gen, CHDK loaded in ARAM, camera_set_led fixed