[WIP] Upgrade to LibGit2Sharp where that makes sense

Opened early for your pleasure and your feedback!
@amitapl Hmmm. Something indeed went wrong. I've got both a `node_modules` and a `bin\node_modules` hierarchy. The first one seems like a day older. I dropped both of them and rebuild only generated the `bin` folder structure.

I'm going to drop this commit as it's useless.

Thanks a lot for this. Nice catch!