[Cmake] I want to add a QT wrapping command to CMake

[John Biddiscombe]

>I would like to automate the process, and I was thinking of copying the
>VTK_WRAP_JAVA command, creating QT_WRAP_CPP command.

I've used two approaches.
1) Copy VTK_WRAP_TCL and create a VTK_WRAP_GUI command which does stuff to 
each source file. This is straightforward if you copy the existing stuff 
and just change what you need. VTK_WRAP_JAVA is presumably the same.
2) I found the above a bit tedious as I'd rather wrap all the files in one 
go rather than one by one (superclasses were not "there" when I needed 
them), so I added a command which simply generates a list of stuff in a 
file like cmakelists which my wrapper can scan after cmake has finished.

Both worked fine and you shouldn't have any trouble modifying a wrap 
command and adding it as a new one.

JB