Add command line view to PasHiGUI

[delphidabbler]

It would be useful to be able to see the PasHi command line used by PasHiGUI when it executes PasHi.

Possibly use an optional pane displayed at the bottom of the window, or even a floating window?

[delphidabbler]

See also issue #60 that proposes adding a window to view PasHi's output.

Could the two views be combined?