Allowing arguments to be passed to _python

I'm brand new to fish so I'm not sure if this is a fix of if I'm doing something incorrectly.  On fish version 2.1.0 on osx 10.9.2 running pyhttp doesn't start the http server, instead only starts the python shell.  This fixes that issue for me at least.
Merge pull request #149 from vincentjames501/master

Allowing arguments to be passed to _python