[#76] Have requirements in setup.py, only testing requirements in setup.py
[#76] Add note about new requirements to contributing
[#76] Properly install requirements on travis
Merge pull request #76 from okfn/76-requirements-clean-up

requirements-test should not contain normal requirements
Adds support for Open Spreadsheet format files (*.ods)

Unfortunately for large files existing libraries are not particularly good
at handling them.  large.ods shows a 2Mb ODS file that expands out to 10Mb
and odfpy uses Gb's of RAM and takes over a minute to load it.

Although not particularly pretty this version has judicious use of regex and
XML parsing to pull the relevant information, and can process 26k rows in a
10Mb content.xml in approx 5-7s.
PEP8 and import clean up
PEP8 and housekeeping