Making a basic javascript API for the toolbar.
Updating JS api documentation.

Removed parameters to show_toolbar and hide_toolbar.
Removed extra whitespace and added a tab after a long param description.
Fixed copy-paste error for method summary for djdt.cookie.set
Merge pull request #619 from tim-schilling/javascript-api-484

Add a JavaScript API. Fix #484.
Make note of the incompatability with the GZipMiddleware.