[Fusion] Cursor change for radius, polygon selection tools

[jfournier]

Usability: When Measuring, Selecting Radius or Polygon the cursor could change to indicate the mode. There is no temporary radius indicator as in the old Web Layout. There is no key sequence to exit the mode and return to a default of Select?

Note: we could add cursor as a general property of widgets.

Note: we will find a more suitable default cursor for these selection tools, possibly the crosshair cursor

Note: the ESC key should be hooked up to escape the current operation when drawing

Note: we cannot return to normal Select mode. This is a design restriction of fusion.