Added Paper.js to project and copied the baseline tagging_interface template from the cq_interface template.
Added tagging interface to base html template.
Oops.  JavaScript syntax error.  Fixed.
Added a Paper.js-based canvas to accept drawn user input.
Just an intermediate checkpoint.  Working on zooming the tag view window.
Looking pretty good.  Now for the data half.
Added a ManualTag model to collect tagging data.
Nick approves of the tagging interface.  Time to wire it up.
Intermediate checkpoint.
I don't see why new rasters are translated yet, but it's otherwise working.
Still don't understand what's going on with Paper.js.  Won't redraw until click.
Really close.  One more .setCoords() to find, looks like.
Switched to Fabric.js from Paper.js.
The tagging interface is now working.
Merge pull request #37 from wil-langford/tagging_interface_raster_by_url

Tagging interface with jQuery and Fabric.js.