Re-enable Python MLlib tests (require Python 2.7 and NumPy 1.7+)
Complain if Python and NumPy versions are too old for MLlib
Merge pull request #462 from mateiz/conf-file-fix

Remove Typesafe Config usage and conf files to fix nested property names

With Typesafe Config we had the subtle problem of no longer allowing
nested property names, which are used for a few of our properties:
http://apache-spark-developers-list.1001551.n3.nabble.com/Config-properties-broken-in-master-td208.html

This PR is for branch 0.9 but should be added into master too.
(cherry picked from commit 34e911ce9a9f91f3259189861779032069257852)

Signed-off-by: Patrick Wendell <pwendell@gmail.com>
Merge pull request #426 from mateiz/py-ml-tests

Re-enable Python MLlib tests (require Python 2.7 and NumPy 1.7+)

We disabled these earlier because Jenkins didn't have these versions.