Changeset : DATE_STAMP propcase for propsets 2 and 4, mycolors propcaes fro propset 4, ...

DATE_STAMP propcase for propsets 2 and 4, mycolors propcaes fro propset 4, from msl in ​http://chdk.setepontos.com/index.php?topic=650.msg101945#msg101945 and waterwingz in ​http://chdk.setepontos.com/index.php?topic=650.msg101953#msg101953

Update for code_gen.
Split chdk_dasm.c code into seperate files (potentially reusable).
Fix 'LDR PC,=' output to work like branch.
Remove global variables from stubs_load.c (to allow multiple firmware files to be loaded).
Add latest chdk_dasm fixes from srsa_4c.