Changes for 2.0.3

• Improved data binding of tooltips and context menus for item panels to avoid temporarily setting Panel.data incorrectly.
• Enhanced the meaning of UndoManager.maxHistoryLength so that a value of zero causes no Transactions to be remembered in the UndoManager.history but allows commits and rollbacks to occur normally.
• Fixed a bug from 2.0.1 with Diagram.makeSVG incorrectly re-using SVG elements.
• Fixed a bug from 2.0.0 with Diagram.makeSVG when drawing dashed paths.
• Deployment fixes for electron apps.