index: Use relative paths so the page isn't broken when mounted elsewhere

When developing locally in a different path (e.g.
http://github.dev/tools-labs/static or http://static.github.dev)
it now works as expected. It also makes it future proof in case
the project gets renamed or re-used elsewhere.
Add "Fork me on GitHub" img to static
Load forkme image from local instead of s3.amazonaws.com

Fixes #5
Merge pull request #6 from Krinkle/updates

Various updates