[doc] Update README

Update the readme to point to Travis CI logo, and also to the GitHub and
PyPI locations for getting the package rather than Google Code.
[travis] Update Travis to install dependencies correctly

Add correct commands to install numpy, scipy and cvxopt. Cvxopt is
always built from source and requires several development packages.
Numpy and scipy are installed from packages on Python 2.7 and 3.2 in one
case, but built from source also. Scipy is built from source on 3.3 and
3.4.
[checking] Catch sparse matrix comparison error

The sparse matrix error changed and and NotIMplementedError had to be
causght also to check that also elements of a transition matrix are
non-zero.
[tests] Replace mdptoolbox.utils wth .util

The mdptoolbox.utils module was renamed to mdptoolbox.util and the tests
were still using the old name, Replace all occurances of utils with util