Added LitecoinBlockHeaderAttestation

[cloutier]

This is the first step to support Litecoin. I still need to implement full verification, but the lite one with insight works.

There is a PR open here to define the tag for Litecoin.

I have a LTC server here: https://ots.ltc.catallaxy.com/ . The code (which is really hacky and going to be redone anyway) is here: https://github.com/cloutier/opentimestamps-server/tree/litecoin

I am going to update the exemple for multiple blockchain also, but https://eth.ots.eternitywall.com/ seems to be down at the moment. But here is an exemple timestamp in the interim: Archive.zip

[RCasatta]

Hey,
Thanks for this effort and sorry if I took much time to answer.
I am closely following this opentimestamps/python-opentimestamps#20 and I consider that a requirement to merge also this one to have compatible libraries.
In the meantime, would you consider checking why the travis build is failing?

[RCasatta]

The build is still broken just for linter problems, could you have a look at the just added section in the readme?

[cloutier]

Thanks for the feedback! I think I have fixed all the tests, but I'm a bit confused about this remaining error (only on node 6.1):

test/open-timestamps.js ............................. 28/29 30s
  not ok test count !== plan
    +++ found
    --- wanted
    -1
    +28
    results:
      ok: false
      count: 28
      pass: 28
      fail: 1
      bailout: false
      todo: 0
      skip: 0
      plan:
        start: null
        end: null
        skipAll: false
        skipReason: ''
        comment: ''
      failures:
        - tapError: no plan