Switch to ByteBuffer for Protobuf read and write
Remove max AIS size setting
Remove SerializationType
New metadata layout in PSSM
merge nathanlws: New, and simplified, (PersistitStore)SchemaManager metadata storage

Merge pull request #1002 from nathanlws/sql-layer/new-schema-manager-metadata
https://github.com/FoundationDB/sql-layer/pull/1002