corlib and JIT updates

[ncave]

@SteveSanderson

Here are a few fixes and updates to the corlib and JIT:

• Better C# support (added some missing JIT features, some bug fixes and updates).
• Added F# support if needed (uses custom FSharp.Core, see here for a working example).
• Updated the DNA JIT VS project (very helpful for debugging JIT issues).
• Tried my best to keep the corlib light, it's still 250k (in release mode).
• Release build assemblies work now too (after JIT bugfixes).

I heard you added CLR debugging in the browser, that's awesome!

[SteveSanderson]

Thanks @ncave, this looks really great!

It's going to take me some time to be able to merge this, because there's also a ton of updates in the Blazor Hackathon repo (e.g., debugging support) that I also need to merge back selectively to this repo, and I don't know how cleanly that large changeset will combine with yours. At the very least it will be about 3 weeks before I'll be able to attempt this.

If, when you did this work originally, you had it as a set of independent commits that addressed different bits of functionality, it would potentially be useful to see the PR in that form (multiple commits) as it could make the merging easier.

[ncave]

@SteveSanderson Unfortunately the changes were made in a different repo, but the ones included in this PR are confined to the DNA folder, so hopefully they are orthogonal to yours and will just blend in. Thank you for the hackathon link, I didn't know about it. I'll take a look to see if there are any merging issues that can be resolved ahead of time to simplify your task.

[ncave]

Closing in favor of this PR in the hackathon where all the merging issues have been resolved. Hopefully that helps.