Added ipython, pyzmq & tornado to requirements

Not having ipython installed in the virtualenv can make headaches.

ipython also does not list its dependencies - pyzmq and tornado, so they had to be added too.
Add zmq devel package to allow zeromq to install
requirements has some hints for devel packages now
Merge pull request #383 from seandst/origin/ipython-requirements

Added ipython to requirements