Update references to new project location

* Change 'github/gollum' references to 'gollum/gollum'
Merge pull request #652 from simonista/update-references

Update references to new project location
Update README.md
Add basic support for symbolic links.
Merge pull request #658 from cpence/master

Basic support for symbolic links
Fix symlink base path, don't allow symlinks in bare repos.
Merge pull request #659 from cpence/master

Fix symlink base path, don't allow in bare repos
Fix for embedding code from github
Add option for custom js (like custom css)

* Add a new 'js' flag to indicate you want to embed a file named 'custom.js'
  which should exist at the root of the wiki
[[_]] float clearing tag experiment
Move gollum back end to gollum-lib #647
Merge pull request #662 from lemonsqueeze/clearfloats

[[_]] float clearing tag experiment
Fix style
Merge branch 'master' into feature/gollum-lib

Conflicts:
	lib/gollum/markup.rb
Merge pull request #661 from simonista/custom-js

Add option for custom js (like custom css)
Update README.md
Update README.md
Merge pull request #660 from simonista/fix-github-links

Fix for embedding code from github
Merge branch 'master' into feature/gollum-lib

Conflicts:
	lib/gollum/markup.rb
	test/test_gitcode.rb
Merge pull request #664 from jamieoliver/feature/gollum-lib

Move gollum back end to gollum-lib #647