Add support for injecting arbitrary JavaScript to API docs
Dynamically add badges based on annotations

This has known problems due to bugs in scaladoc. In particular, on the
packages page, annotations appear only if there are no comments for the
element. As soon as this is fixed (or there is a workaround) this should
basically be ready.
Add identifier tags in comments to work around scaladocs bug

The bug is that annotations and comments cannot both be displayed in the
summary page. The workaround is adding a special pattern that we grep for
as we post-process the DOM tree in JavaScript.

Example: A @DeveloperAPI annotated class's comment must begin with
":: Developer API ::"
Comments and new lines (minor)
DeveloperAPI -> DeveloperApi
Merge pull request #1 from andrewor14/annotations

Replace all <span>...</span>s with annotations