StreamingState: add a method to create a new instance based on the current one.
IDBController: add the implementation of sync mode
add a test to check IDBController sync mode.
Merge branch 'master' into jwang_IDBSync
Merge branch 'master' of github.com:uwescience/myria into jwang_IDBSync
fix test
change boolean to Boolean
Merge pull request #577 from uwescience/jwang_IDBSync

Jwang idb sync