sort options to make --help output prettier

explicitly sort options when adding them to argparse.
it's a bit silly to print them in a dict iteration order.

Change-Id: Id508331d7ee3b24e76be7fa958d27d29905bd3d2
Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Merge "sort options to make --help output prettier"