WIP 0.3.8
added support for app-settings kanso package.

Saving settings in dashboard was too slow for use because entire ddoc
was being updated.  Using app-settings API fixes that.
modified messages export filters to include all data records. Fixed #502

Base startkey/endkey filters on date value instead of '*'.
updated sentinel submodule
updated ci/after_success script to deploy master to release market.
added 0.3.8 changes log entry