Put examples directory at the top level, so that they be easily imported for tests.

From: cdavid <cdavid@cb17146a-f446-4be1-a4f7-bd7c5bb65646>

git-svn-id: https://scikit-learn.svn.sourceforge.net/svnroot/scikit-learn/trunk@97 22fbfee3-77ab-4535-9bad-27d1bd3bc7d8