Work on keystroke acceleration for IJ2

[bdezonia]

Figure out how to get keyboard accelerators to work in IJ2. Implement in Swing and AWT UI's. Learn from IJ1 as appropriate.

[bdezonia]

Determined the correct syntax to use in plugins. Implemented these changes in current plugins. Changed code in IJ2 to support Command/Control differences for Mac/other OSes. Allow ^{X as shortcut for "control X" in plugin accelerator definitions.}

[bdezonia]

TODO - learn how to put accelerators in AWT menus and then implement for out AWT UI. Pretty sure code can be stolen from IJ1. Come up with UI agnostic way to support adding menu accelerators and then use in AWT & Swing UIs.

[bdezonia]

note - if this will take more than a few hours push to another milestone

[bdezonia]

Implemented an Accelerator class in AWTMenuCreator that enables keystroke accelerators in the AWT UI. This class is large and does not support all uniocde or non-QWERTY keyboard layouts. (The QWERTY issue arises because there is no KeyStroke key code for some characters such as question mark). It does however avoid a Swing dependency. The Accelerator class should be moved to its own class. But maybe we should retire it completely and require the AWT UI to have a Swing dependency. If we run into systems that have AWT and not Swing we'll address this issue at that time.

[curtis]

Our recent work on the AcceleratorHandler global tool may be of use for supporting accelerators in the pure AWT implementation.