beta-2

We have around 60 commits since previous beta, and @andrewbird joined
the development. :)

• 32bit support resurrected (thanks Andrew for testing)
• better dosemu2 integration (boot sector extension to pass command.com drive)
• DPMI apps are now working reliably, windows-3.1 works
• valgrind and ubsan fixes (ubsan found some real bugs!)
• lots of work on memory management, object tracking and thunk dispatching
  (but not yet complete)
• drop all hopes of C++-less run-time: libstdc++ is now and forever a mandatory
• FCB subsystem ported, with additional fixes from Andrew
• many bugfixes