Further fix type name demangling under MSVC
Further fix type name demangling under MSVC

- Renames the MSVC annotation stripping function to 'demangle', so that
  demangle(typeid(X).name()) works under all compilers (this is needed
  for the Instance reflection function).
- Also replaces the "+1" hack (which stripped the leading 'P' from the
  gcc-mangled type name) with a more robust and cross-platform method
  that directly strips the corresponding '*' from the demangled type
  name.

NVIDIA/jitify,NVIDIA/jitify