More formatting changes
Gave Environment.setVar better handling for integers/floats

Lots of complex code, but now it actually allows us to follow VB's
widening and narrowing conventions for integers and floating-point
values. Work will need to be done at some point to this code for Enums
to go to their matching types.
Added FsCheck 0.9.3 from NuGet with some simple sanity checks

Set up FParsecScriptHost to run the sanity checks when called with
"test" as the only command-line argument.