Implement a WiX installer for Windows

All that is required is a freshly-generated UUID, an installation of WiX, and
it's good to go.  It assumes the project was built with VS2010, but it's just
the runtime DLLs that would need to be tweaked.
Configure various variables automatically in the WiX installer automatically via CMake

Also renaming the source files for the installers so that their type is picked
up easier by editors.
Simplifying NSI script
Adding installer dialog customization help
Final documentation changes