Code formatting

[dtebbs]

Introduce a code-formatting tool to ensure style consistency across the code base.

[AntoineRondelet]

This PR addresses issue #57

[dtebbs]

I did another iteration addressing a few places where the results of the formatting stood out. As before, I've pushed a final commit with the formatting.

I just did a very rough scan, so there are still bits of code that will be formatted strangely until somone manually addresses them (mainly comments at the end of lines). But we could address those later as the code is touched in future commits.

Let me know if anything stands out as wrong.

[dtebbs]

I just have a few more places to fix, and then I'll remove the WIP from this PR.

[AntoineRondelet]

The PR looks good to me. However I have a compilation issue:

snarks/groth16/computation.hpp:25:14: error: ‘extended_proof’ is not a member of ‘libzeth’
     libzeth::extended_proof<ppT> ext_proof,
              ^~~~~~~~~~~~~~

It might be an error with some of the "includes", maybe the extended_proof.hpp is not properly included in the computation.hpp

[dtebbs]

It might be an error with some of the "includes"

Thanks. I think there were some circular includes shown up when clang-format reordered things. Should be fixed now, along with a rebasing error I introduced.

[AntoineRondelet]

Thanks a lot for that @dtebbs good to have some tooling to improve code consistency.
LGTM.