sx210is: modemap corrections, minimum ISO override limited to 60 to prevent a crash when flash is active, enable autobuild
http://chdk.setepontos.com/index.php?topic=5045.msg99862#msg99862
Fix 'Dark Frame Subtraction' override for G15 & SX50.
Fix nrflag detection for newer cameras.
Fix SVN properties for A2400.
Fix focus_len_table detection for D20.