Single Instance Multi Window (v2.0.0)

Using ipc to ensure single instance mode for GUI applications (convertor usage still allows multi-instance).
Attempting to create a 2nd Gui Instance will have it shut down and launch a new GuiApp/MainWindow instead.

Initial Test (v1.0.0)

Initial parent launcher with child processes for GUI applications.
Launching in console/converter mode keeps that instance as a stand-alone instance.
Launching a GUI app will check for IPC server, if there isn't one, this instance becomes the IPC server and acts as the launcher.
If an IPC server is found, and we weren't launched by it, this instance asks the launcher launch itself as a child and quits itself.

Unfortunately this approach still shows separate top level process entries in Windows Task Manager and is expected to remain multi-dock-instance on MacOS as well..