[Vm-dev] Some VMMaker updates, CPP generation and Mantis 5238 fix

[David T. Lewis]

I have made some changes in VMMaker to resolve Mantis 5238 (Integer bug on
64bit image/32bit VM, DateAndTime now ==> -4391-12-26T16:18:33+00:00),
which is a long-standing issue that affects Squeak 64-bit images.

VMMaker-dtl.133 adds support for C preprocessor statements in Slang. This
has no effect on the generated code for the interpreter (until of course
you use one of the new Slang methods), but the changes touch quite a few
methods and are likely to be an annoyance for anyone who may be maintaining
a separate VMMaker project.

VMMaker-dtl.134 has a new implementation of #isIntegerValue: that resolves
the Mantis 5238 concern. This does change generated the C code (cosmetically),
so I added it in a separate Monticello change to allow sceptical readers to
separately verify that the C preprocessor support is not causing problems. 

Dave