Update build documentation to include using CMake GUI

[blowekamp]

No description provided.

[blowekamp]

@dave3d Can you handle this one?

[dave3d]

I was making the images for this, and thought, this feels really familiar. Haven't I don't this before? So I looked around the SimpleITK docs, and found it:

https://simpleitk.readthedocs.io/en/master/link_CppCMake_docs.html#using-cmake-on-windows

Is this what we want? If so, we can just move it or something.

[blowekamp]

https://simpleitk.readthedocs.io/en/master/link_CppCMake_docs.html#using-cmake-on-windows

That section was suppose to be: How to use the CMake GUI to build an example/project that uses SimpleITK.

This issue if for how to build SimpleITK itself with the CMake GUI. The link you provided looks like it describes the latter, and not what is was suppose to illustrate.

[dave3d]

Gotcha. So I'll move that text to a new page, and re-do that section.

[blowekamp]

@dave3d If you completed this please link the PR here and close :)

[dave3d]

#1387

[dave3d]

Done.