v0.3.0

Changelog

• be85f6f _catalog.json
• 68c194c README updates
• 58e6917 _sdc_surrogate_key required
• e3a0392 begin catalog, remove db
• e2f7dd1 begin refactor of channels and root extract
• bc1f467 comment for reference
• b33d3e7 fix concurrent state look-ups, simplify using map of empty structs
• 9646699 introduce mutex to handle concurrent writes
• 7751ea4 schema updating fix
• 47932cf update pointer referencing in ProcessRecord
• 42f4d4a update record processing logging
• c6e8dc2 v0.3.0, README updates