Merge pull request #7 from glouppe/website

Mr. Proper, act 1
add section, estimator and model links on the frontpage
fix styling of rst links
add links for examples
Banner improvements
Banner style
Merge branch 'redo_website_yet_again' of github.com:amueller/scikit-learn into website
fix css that I just broke with the sphinx links
Merge branch 'redo_website_yet_again' of github.com:amueller/scikit-learn into website
Boxes on front page