Use gcc/clang demangler for NiceTypeName.
Improve type name demangling.
Fix memory leak if status !=0.
Include cstdlib to get std::free().
Get demangle() working on Windows.

1. Include <string> on Windows.
2. Export the demangle function.
Only free demangling output if demangling succeeds
Merge branch 'demangle' of github.com:chrisdembia/simbody into demangle
Correct my use of SimTK_SimTKCOMMON_EXPORT.
Merge branch 'demangle' of https://github.com/chrisdembia/simbody into demangle
Merge pull request #223 from chrisdembia/demangle

Use gcc/clang demangler for NiceTypeName.