Compare outputs from postprocessors (#62)

Added two commands: `Autodesk HSM Post Utility: Change secondary post executable` and `Autodesk HSM Post Utility: Compare post processors`.

`Autodesk HSM Post Utility: Change secondary post executable` allows users to browse for a post.exe.
`Autodesk HSM Post Utility: Compare post processors` runs two different post processors and opens a diff. If either post.exe is not selected, then the user will be prompted to select it and run the command again.


* Add commands to set a secondary postprocessor and to compare both postprocessors

* Stop selectedCNCFile from post processing when called from post compare

* Move parameters setup into a new function

* Change newDebugger to be an argument of createParameters

* Open log if secondary postprocessor fails

* Find legacy post processsor automatically for secondary post processor