allow ProgramPath to be overridable via an environment variable

[leontristain]

Closes #16

Hi Mator, when last we talked about #16 (over a brief conversation on discord and then a reddit message), you mentioned that the Hardcoded.dat files are going away, so for a while I waited for your new update. Since it's been almost a year now and still no update, I figured I'd give it a stab.

I'm hoping that if you're okay with the code, then perhaps this can get the tiniest minor version release (like maybe v0.6.1) built out. With it, there would no longer be a blocker for me uploading my python wrapper to PyPI. Meanwhile when you do get around to removing the Hardcoded.dat files, there's no need to preserve this after.

I tested this change manually with GetGlobal and ElementCount and it seems to have the desired effect. That said, I've never worked with Delphi in my life and just getting it to compile took a few hours. The dll I built out seems to error on some more advanced xedit-lib workflows beyond GetGlobal and ElementCount, which I chalked up to project configuration issues, but if there's something egregiously wrong with the code please let me know.

Thanks,
leontristain

[matortheeternal]

Hi, thanks for the PR. I'm actually just about to push the release which removes the dat files, so this is a bit poorly timed. The release is operational on the branch https://github.com/matortheeternal/xedit-lib/tree/feature/xedit-4.x

I can send you a pre-release if you'd like.

[leontristain]

@matortheeternal Wow nice! Not a problem at all. I didn't know 4.x was going to happen so quickly. This is exciting.

Yes I would like a pre-release if you don't mind, that way I can jump onto making any needed updates to my wrapper asap.