Updates/refactorings for mlp and srn, addition of rbf.

From: fred.mailhot <fred.mailhot@cb17146a-f446-4be1-a4f7-bd7c5bb65646>

git-svn-id: https://scikit-learn.svn.sourceforge.net/svnroot/scikit-learn/trunk@32 22fbfee3-77ab-4535-9bad-27d1bd3bc7d8