bugfix: Just copy base node plugin files rather than syncing.

This circumvents an apparent bug in the way Gradle sync works
with symlinks in the target directory on certain FS's; it attempts
to list the contents of all symlinks as if they were directories,
and errors out as the filesystem responds with a failure.
Don't proxy same-server http requests.

Just have the client load the http document from the beaker/bunsen
server directly rather than sending the request around the mulberry
bush.
Add Authorization header to same-host requests.
Add the Bunsen Save menus to Beaker.