Refs #23: Reorganize static files

* Move most static files from symposion/static to
  pycon/static
* Move site_media dir from under symposion to top-level
* Update settings and .gitignore appropriately
Undo some changes PyCharm seems to have made to some .less files when I moved them
Merge pull request #23 from caktus/feature/reorg-static

Re-organize static files