Implement NGC save/load in hs-toxcore and run round-trip tests against c-toxcore

[iphydf]

A new section type needs to be added and documented here: https://github.com/TokTok/hs-toxcore/blob/24ee6e2c3dc1d1565558c14705723228f5fdad6a/src/Network/Tox/SaveData.lhs#L116

Then it needs to be added and parsed here: https://github.com/TokTok/hs-toxcore/blob/24ee6e2c3dc1d1565558c14705723228f5fdad6a/src/Network/Tox/SaveData.lhs#L266

Then a test like this needs to be added: https://github.com/TokTok/hs-toxcore-c/blob/57d3c85f4042ea69c15916f58ebc5ec30a5af1ad/test/Network/Tox/Types/EventsSpec.hs#L59

And we should run that test against c-toxcore to make sure the documentation agrees with the implementation.

[iphydf]

TokTok/hs-toxcore#218

[iphydf]

Mostly done. The rest just needs the save format to be made more msgpacky.