Tidy conceptdiagram css up a bit
Remove now unwanted generic debugging message
Handle renames from outside conceptdiagram plugin

Slightly overhaul the way we frame the label rename
logic: it's not the current label overwriting the
previous one; it's more committing a provisional
label over the current one.

The plugin reflects the provisional label (something
you may be typing in but haven't hit enter on yet)
Less annoying concept mouse-out behaviour

I'm trying to smooth out an annoying interaction in trying to rename a
concept. Before this commit, I would lose focus in the middle of
selecting the concept label because I would unconsciously click-n-drag
as though I were highlighting text, and in doing so would often bump
the mouse out of focus, which disables everything.

Now, once you click the text label, we ignore the mouse-out until you've
typed at least a character in the box
Mechanism to display label for concept

This is mostly for live debugging.
Better conceptdiagram renaming

Rather than directly setting the rdfs:label property, package
everything up in some kind of annotation property frame. Doing
so causes webprotege to fire events that the rest of the system
recognises.

For some reason, prior to this change, renames would only work
until you try renaming from outside the diagram. We would
recognise such renames (and subsequent ones), but after that
point, our renames would not be picked up on by the rest of
Webprotege.