un-tarbombed requirements.txt

I'm not 100% sure that this contains ALL the requirements, but for the love of god, ipython isn't required, and shouldn't be shoved into a library's requirements.txt.

prune method:
for each module in old requirements.txt, did `python -v -c 'from gittle import *' 2>&1 | grep <module>`.  If nothing showed up, I removed the entry from requirements.txt

If this does not get pulled, I would not be surprised, but please keep the requirements.txt to the ACTUAL requirements of the module, not just whatever happens to be in `pip freeze`

P.S.:
bpython > ipython