Use django compressor for CSS and JS files

The app combines CSS and JS files into one, reducing the number of
requests and hopefully making the website faster. This is specially
important for the mobile version.
Fix link URL
Update D3 library

--HG--
extra : amend_source : 220a343e7849b09a49229bc0edc4fff38f69c01d
Add Russian translation file for jQuery datepicker
Add link to repository folder with datepicker translations
For more consistence, use a listview when workout has no days
Don't translate generated filenames, makes trouble with unicode