Use WiX to generate an MSI-based Puzzles installer.

Use WiX to generate an MSI-based Puzzles installer.

I've reused most of the install script I wrote for PuTTY recently,
minus the selectable-features dialog, and plus some preliminary Mason
templating to automatically build the right set of puzzle binaries
into the installer.

Stable GUIDs are autogenerated by the same technique I use in PuTTY's
Visual Studio project file generation: hash a fixed pile of randomly
generated bits (that is, randomly generated _once_ and used forever)
with each filename or other identifier and use those as your random
number source.