Normalize the string -> obj pairs

[777arc]

eg START_INDEX_KEY should probably be renamed to CORE_SAMPLE_START, along with all the others that clearly dont match

[Teque5]

Yep, this should be done along with #92 and throw a deprecation warning when accessing the old key.

[gmabey]

I would add that such variable-value pairs should be generated automatically (albeit through a manually-invoked process) with some python foo. Same for the extensions (after they are converted to JSON schema).

[777arc]

Yeah good idea, as long as there are generated docs to go with it. E.g. colon -> underscore and capitalize everything.

[777arc]

could also use SAMPLE_START instead of CORE_SAMPLE_START