Now for the major refactoring.  Introduce mod_isapi.h, as we have had
  untold problems with compatibility between different Visual Studio and
  PlatformSDK users [based on their generation of the MS ISAPI header.]
  This header is coded from scratch in native APR types.

  Replace the apr_array_t with an apr_hash_t, mutex protected, to allow us
  to preload and late-load isapi modules.  This closes a significant bug
  with trafficed sites using uncached isapi modules, where one would be
  closing the module just as another request is opening it [as if for the
  first time.]  This would cause some ISAPI modules to crash.  Now that
  we load modules for the lifetime of the server, a simple graceful restart
  is all that's required to unload all the non-precached modules.

  Crack out all FAKE_ASYNC code while we complete it.  Total support for
  the Completion Context callback and end-of-request termination is required
  before we can toggle this on.

  My next commit; complete fake async support.  But t...