fbgrab: bump verstion to 1.3

Changelog (see [1] for details):
  - Added support when active framebuffer is not starting at offset 0
  - Fixed broken re-ordering of colors, rgba to argb
  - Fixed broken path for man page

[1] http://fbgrab.monells.se



Signed-off-by: Peter Seiderer <ps.report@gmx.net>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>