Needed for the impending enabling on *nix platforms

A file included by the source that implemented various ToString
converters of reflection data to strings itself depended on those
declarations, which it only found because of the unique way MSVC
processes templates. By moving the definitions and declarations into
their own header and source files, everyone gets what they need
without ouroborosing.

Creates the DirectX-Headers submodule and adds the needed defines to
allow them to be used. As yet makes no use of these headers

The check for the file stream that is meant to represent the filechecked
source file wasn't sufficient to detect a non-existent file. By expanding
the error check, it can produce a helpful message.

Also initialize the failure code so it isn't random

This flips the switch, removing or repositioning many ifdefs and
including previously excluded files in the build.

…o linflection

What compiler is overly permissive now huh? huh? (or just quick to adopt
new language features?)

Loathe as I am to push one more commit onto this. I don't want to
propagate a misconception. I meant to remove this earlier and caught it
from one final self-review >:(