Allow -p and -a option for run-backend and run-frontend.

Fixed #28. I also make -x option, which specifies the root directory (instead
of the original implicit $2 being the positional argument for the root directory path)

Conflicts:

	setup.sh
Allow command to be in the first position rather than the last. See #28.

The problem with getopts is that it cannot handle non-optional args before
optional arguments apepar.

So ./setup.sh run-backend -x ./ will not work unless we shift $1. This patch makes
the code a bit cleaner.
Merge pull request #29 from yeukhon/master

Allow -p and -a option for run-backend and run-frontend