[dev] spacebed pull request to accept client as argument

I really wanted to use spacebed as a generic tool for spacebing any XNest-aware
client, but the current code would require I have a seperately compiled
version for each client (spacebed-surf, spacebed-xterm, etc) The attached pull request
is my solution. It allows an invocation like:

./spacebed xterm -into

or

./spacebed surf -e

-- 
Stephen Paul Weber, @singpolyma
Please see <http://singpolyma.net> for how I prefer to be contacted.
edition right joseph