Matchmaker V1 API

Approved by reps from PhenomeCentral, GeneMatcher, and Decipher
Ported to Avro from https://docs.google.com/document/d/1yCmDoOpkH9SpFwyQ-QGApZw8HMwFpzQLILIqI1tUFDY

Merge pull request ga4gh#158 from pcingola/Circular_genomes

Added comments clarifying how to handle coordinates in circular genomes

Merge pull request ga4gh#104 from cassiedoll/readCount

Remove readCount field