Added installer, fixed release mode float issues

Apparently floats behave different depending on release/debug, and
depending on whether it's run under the VS context.  Anyway, the slicing
code is more robust now.

Also added a Wix installer project.  Just build Release in VS and run
"run.bat" in the install folder.  Need to remember to keep the *.xml
file updated whenever a new assembly is added - possible future task,
automate.