cleanup and responsive design, menu bar

Big cleanup of source code (removed tons of unnecessary markup like 3 nested tables with absolutely no use)
page is now responsive for all screen sizes
added a first draft for a menu bar with fixed position with the typical winpython colors

TODO: improve menu and check browser compability (IE?)
final release
Merge pull request #6 from stonebig/master

final release
CSS fixes: hyphens, background of content box
Merge sebix/redesign with master