Changes the Proportional Point editor
Changes made according to #319. I've basically added a UIPanel dedicated
to the stroke and fill management.
Merge pull request #376 from agueganno/feature/proportional-panel-improved

Changes the Proportional Point editor
Circles seem to be roudn again.
It has cost more to understand that it was not a Shape but a
RenderingHints problem, but well : it should solve #367.
Merge pull request #377 from agueganno/improvement/round-circles

Circles seem to be round again.
Groups actions listed in the TOC menu.
See #160.
We don't need to implement property support for JComponent !
Removing it and using the one from Swing fixes #379. Lazy initialization
would have done the trick otherwise, but this one is better...
Merge pull request #378 from agueganno/improvement/toc-menu-order

Groups actions listed in the TOC menu.
Merge pull request #380 from agueganno/fix/NPE-finally-379

We don't need to implement property support for JComponent !