Allow updating profiles #26
Description
Currently, users can install profiles from the web, but they cannot update them from the original source URL. We should add a command to examine the changes between a profile and the source URL, which will tell the user what the differences are, and give them the opportunity to download the new one.
Updating a profile should use the <profile_name>_original.json file to determine what has changed, and should not add back addons which the user removed, nor remove/modify addons which the user had modified.