Add support for auto-managing prefixes

[paperclipmonkey]

The editor should support auto managing prefixes. The ui for this would remove prefixes from the query and support automatically adding any prefixes expressed in the query back in before sending the query off for execution.

• Hover over text in query to see expanded uri for prefix.
• Ability to turn auto-manage on and off for a query.
• Auto search for required prefix on prefix.cc