Merge pull request #145 from chapmanb/master

Fix for bx-python build issue and potential fix for bottle.py import error
Update requirements.txt
for install-data.py to write absolute path to the yaml even when run with a relative path.
Merge pull request #150 from brentp/abspath

for install-data.py to write absolute path to the yaml even when run wit...
Fixes for reported installation issues: new version of ipython-cluster-helper with only IPython 0.13.2 requirement; better error message for missing configuration data; only require configured data when doing loading to allow other functionality to work without data files. Thanks to Amit Indap