[Cmake] Drag & Drop support

[Sebastien BARRE]

Hi

We noticed during recent VTK courses that some of our users are trying to 
drag&drop CMakeLists.txt file to the CMakeSetup shortcut on the desktop.

This actually opens CMakeSetup, but does not set any directory.

I've just added Drag & Drop support to CMakeSetup (filenames only).

CMakeSetup will accept:
   - a directory name (source and build dirs are set to this name),
   - a file name (source and build dirs are set to this file's directory),
   - a CMakeCache.txt file (the build dir is set to this cache's directory, 
the source dir is set to the value found in the cache)

You can drag&drop these files either on the CMakeSetup window, or on its 
shortcut on the desktop.

Seb

--
Sebastien Barre