Add "toggle by device" control

ConfigLayouts now includes a "Toggle by device" control. Presently,
clicking it toggles checkmark and does nothing else.

In SetList, when ConfigLayouts is called, we now pass DevNums and list
of device names.
Finished "toggle by device" which closes #28

ConfigLayouts now toggles column display width by device. New utility
DevNum_StartAndSpan takes a DevNum array and gives start + span for
cols.

Bundled DeferPanelUpdates into ApplyLayoutFromUIArray to simplify
calling it.
Merge remote-tracking branch 'origin/master' into improve-layout-portability
Merge pull request #47 from CHerold/improve-layout-portability

Toggle by device in ConfigLayouts.