Add window to PasHiGUI displaying PasHi's output.

[delphidabbler]

It would be interesting / useful for debugging to be able to see any output displayed by PasHi on stderr when it is executed from within PasHiGUI.

[delphidabbler]

There would also need to be an option to set PasHi's verbosity level from the UI for this to be valuable.

It would be helpful to have a special message displayed if PasHi is being run in silent mode.

[delphidabbler]

See also issue #59 which proposes displaying the command line passed to PasHi.

Could the two views be combined?