Closes #224 Adding manual flush methods to all stores so that user can choose how often they'd like to flush
Merge pull request #229 from calrissian/224

Closes #224 Adding manual flush methods to all stores so that user can c...
Cleaning up feature store and making it ready for release.
Merge pull request #233 from calrissian/featureStoreCleanup

Cleaning up feature store and making it ready for release.
Fixes #204.  Use a more efficient algorithm for normalizing the timestamps based on a specific timeunit.