add white balance mode propcase, from nafraf in http://chdk.setepontos.com/index.php?topic=650.msg101858#msg101858 + propset 1
Fix buffer size error in stubs_load.c.
Update stubs_entry.S files missed in previous revision.
Updates for finsig_dryos.c:
- add raw buffer address for cameras with only 1 buffer (suggested by nafraf)
- add MEMISOSTART value, validated against makefile.inc value.
SX160IS port for firmware 1.00a (from nafraf).
http://chdk.setepontos.com/index.php?topic=650.msg101852#msg101852