Rename Concept to Curve

A concept/class can be represented by one or more curves.
Remove unused imports
Tidy up ConceptDiagramPortlet

Try to regroup scattered bits of code into sensible blocks
DEBUG: disable my event dispatch/polling logs
Remove stray debug logs for concept selection
Remove stray debug log
WIP: use IRI based names; support multi-curve

It's a bit tricky for me to untangle the two things here:

- Experiment with assuming that the display name for curve is
  based on IRIs. For now this also includes some trickiness
  like renaming a newly created class to have a new IRI

- Support notion of having multiple curves associated with
  a given class, but ensure that curves can be renamed
  independently of each other. The sort of logic we use here
  is that
  * if we are renaming to a new class, we have to create
    a new class accordingly;
  * likewise, if we are renaming the sole remaining instance
    of that class, we have to do an actual entity rename.
  * in the simplest case this is just remapping things
    slightly
Make dialog boxes obscure everything else

Perhaps not a good approach; we give it an arbitrarily
high z-index and hope that other users don't use a higher
one unless they really want to trump the dialog box
Abort curve resize on mouse out.

It's possible to mouse-out unintentionally.
which leads to a confusing interaction where a curve
gets "unexpectedly" resized because yuo weren't expecting to
still have control over it
Make the notion of a curve counter global.

We centralise the counter so that anybody can create a curve without
running into the risk of id collision
Remove dead code
Tighten up use of Lombok

Try to avoid unnecessary abilities
Ability to create a new curve at coordinates
Remove stray unused class

This was from a time when I was just experimenting with drawing things
Overhaul multicurve support

Switch back to model where we cede control of curve IRIs to
WebProtege.

Instead maintain a 1:1 mapping of iri to name (on the assumption
that it would be confusing to have more than one IRI for a given
name, although note that in the future, we may have to model
1:M)

Also rename ConceptManager to CurveRegistry and try to clean up
the flow of control

Cases I can think of:

- rename a curve to a pre-existing name
- renaming the last remaning instance of a curve
- deleting a curve which has a duplicate
- renaming a curve to something new

There may be scenarios I hadn't considered
Bugfix: repair subsumption curve effects

Regression triggered by 4d88ef4 bugfix.

Underlying cause is that I was using the curve tracking
dictionary to see if it was valid apply an effect, but if
you delete effects they don't appear in the dictionary
which means you don't apply the deletion.

Oops.
Bugfix? base Key equality on object ref equality

I'm a bit confused about whether we need this or not, to be honest