Undo for the greater good

Second release brings Undo/Redo functionality. Press u to undo an action and ctrl+r to redo it. I also fixed some bugs related to deleting multiple selections at once, and a bug around disconnecting boxes. I also added the "What's New" sidebar so you can keep track of recent changes.

Hello World!

Initial release with ability to create a basic flow chart with rectangular shapes. Boxes can be manipulated in a variety of ways: move, resize, change their text, etc. See the Help link in the header for instructions and more information.