VS Plugin make CommandBar permanent (position handling of CommandBar)

Feature request:
 - Make the CommandBar of the VS Plugin permanent (Application.Commands.AddCommandBar)
 - Install it only once in OnConnection Event with ext_ConnectMode.ext_cm_UISetup mode. (This will let Visual Studio handle the position and visibility of the CommandBar.)
 - Update Setup to reset Toolbar to force a reinstall in the IDE

Refs #1299