Remove unused 32-bit Windows support

[hawkowl]

Also prevents building on Windows 32-bit entirely for now, since all v50 are on Windows x64 (I put that in a separate commit so it is revertable if/when 32-bit support changes).

Changes are broken into individual commits for revertability.

[ab9rf]

this stays on hold until we get a confirmation from Bay12 that there will not be 32-bit builds in the future

[ab9rf]

we can probably go forward with this at this point, i'm releasing my hold

[myk002]

I'll fix up the conflicts and merge. Thanks, @hawkowl !