add ReferenceSequence::id and associated changes
add ReferenceSequence::id and associated changes

ReferenceSequence now has an id
move names to ReferenceSequenceSet::names[], and copy lengths to ReferenceSequenceSet::lengths[]
hjellinek/schemas,dnanexus-rnd/schemas,kellrott/schemas,diekhans/ga4gh-schemas,Jeltje/ga4gh-schemas,delagoya/schemas,laserson/schemas,adamnovak/schemas,Jeltje/ga4gh-schemas,lh3/schemas,saupchurch/schemas,benedictpaten/schemas,nlwashington/schemas,lh3/schemas,nlwashington/schemas,ga4gh/ga4gh-schemas,pcingola/schemas,benedictpaten/schemas,buske/schemas,macieksmuga/schemas,hjellinek/schemas,laserson/schemas,dcolligan/schemas,buske/schemas,delagoya/schemas,sarahhunt/schemas,kellrott/schemas,ga4gh/schemas,diekhans/ga4gh-schemas,dnanexus-rnd/schemas,adamnovak/schemas,heuermh/ga4gh-schemas,sarahhunt/schemas,hjellinek/jeltje-schemas-sphinx,dglazer/schemas