TST: CI testing based upon Miniconda with coverage

CI testing using Travis-CI now uses Miniconda to build a Python enviroment.
This allows use to use pre-build binaries of the various required by Py-ART from
binstar.  With this all unit tests are run (none skipped).  This commit also
adds test coverage reporting to [Coveralls](https://coveralls.io/)/
BUG: fixed bugs when running in Python 2.6
TST: do not all basemap in python 2.6
TST: do not install cylp or cvxopt in python 2.6
Merge pull request #118 from jjhelmus/master

Miniconda based Travis-CI configuration