Revised finsig_vxworks.c based on finsig_dryos.c code.
Includes signature verification changes from srsa_4c.
http://chdk.setepontos.com/index.php?topic=10561.msg105578#msg105578
Add signature verification files.
Fix autobuild.
a4000 - 101a fw version also works for 100d
elph320 - 101a fw version also works for 100d. Fix wrong previous patch r3136