Improve table & keyspace creation robustness
Improve table & keyspace creation robustness

- Delay for a schemaSettleTime after each schema change to avoid following
  operations to fail because of schema disagreement.
- Compare JSON of schemaInfos to avoid Object equality disagreements on
  conversion functions. While this might sound inelegant, JSON serialization
  is actually highly optimized and might be faster than a custom object
  comparison algorithm.

eevans/restbase-mod-table-cassandra,gwicke/restbase-mod-table-cassandra