VDrift Data on GitHub

[BiGBeN87]

I do not know C++ and can therefore not supply patches. The SHA1-hashes used by Git and exported by GitHub's API are but perfectly good for identifying versions of content. I proofed the concept of matching local (unversioned) content against Git before by implementing a tool that calculates git-compatible hashes for all of VDrift's Data. Using GitHub's API seems the right way to get the remote hashes and since there seems to exist no client library for the GitHub API in C++, using cURL seems sane. Since all responses of by GitHub's API are valid JSON, using a library to parse them seems to be a fail-safe approach.