Finishing touches for moving docs to Read the Docs

- [x] Rename documentation directory
- [x] Get rid of Eclipse project file
- [x] Move data directory to [Google Drive](https://drive.google.com/#folders/0B8KSMAVGQMrtX1hQVkQzTnBkTFU)
- [x] Update all references to docs location
  - [x] freeseer.github.io
  - [x] freeseer-docs
- [x] Remove stuff we no longer need (e.g. publish script)
- [x] Update code location for auto-generated plugin docs
- [x] Update docs readme (lots of stuff no longer relevant)
- [x] Remove freeseer-docs repo
- [x] Remove everything from freeseer.github.io except index and 404 pages
- [x] Have freeseer.github.io point to new location and redirect after 10 sec
- [x] Update default branch on readthedocs.org (currently set to this branch for testing)
- [x] ~~Remove [freeseer-docs from travis-ci](https://travis-ci.org/Freeseer/freeseer-docs)~~  
      I don't think this is possible at the moment, see travis-ci/travis-ci#987. Instead I disabled build pushes and build pull requests.
- [x] ~~Add sphinx to dev_requirements.txt~~  
      Sphinx is listed in docs/requirements.txt, update the version and improve the installation instructions 
- [x] Update website under Freeseer organization on GH

Closes #450