Set the $user_id global if it's empty
Merge pull request #90 from joshbetz/master

Set the $user_id global if it's empty

props @joshbetz
fix bug with multiple upload fields on a page

Fix a js scope bug that was preventing multiple upload fields to work as expected on a single page. Do so by unbinding prior events before binding new ones.

Also cleans up the function a little bit

fixes #64 and #65
Merge branch 'master' of github.com:Automattic/custom-metadata