Fix MSVC warnings, win64 bug

- Use qSort and function pointer instead of struct operators and std::sort
  to appease MSVC.

- Simplify DFInstanceWindows::map_virtual_memory loop

- Store real base address offset instead of reading 0x400000 from PE
  header.
but i don't like the scanners either, and it would be great for code size if we could rip them out