Add protocol.py

[dcolligan]

Issue BD2KGenomics/ga4gh-integration-deprecated#53

[david4096]

This removes redundant code and will make the schemas python module much easier to use.

[dcolligan]

@david4096 ready for review

[dcolligan]

Actually, hold on... there's a few problems.

https://travis-ci.org/ga4gh/server/builds/199079898

I need to add the encodeValue and setAttribute methods and fix getValueFromValue

[dcolligan]

@david4096 ok, should be good now

[david4096]

CI is failing and I'm not able to replicate locally. It seems like it might be a CI bug working off a different commit? Gonna try closing and reopening.

[david4096]

Thanks @dcolligan. This will move some code that is used across GA4GH installatations (protocol serialization, route information) into the python module. We should be looking for ways to remove the hack and the rewrites we do to the paths. For now I'm glad to have this.

This PR moves some code out of the server and so the PR to attend it is here ga4gh/ga4gh-server#1547 .