Drop logging support, add a simpler 'verbose' option instead.

One can always override "message" method if print is not needed.
Trainer.get_params method for getting all the parameters; more tests.
Cython master is needed because of a bug in cython 0.20.1

See https://github.com/cython/cython/commit/73e24e80bb9722b4bac90e806b76555e2095e002
TST enable Python 3.4 on Travis