Add gevent block start and stop container event action.  Add persisting gevent block traces as part of xls dump
Bump ion-def and pyon pointer
Update pyon and ion-def pointers
Moves the metadata about coverages into the object store

- Adds new method to dataset management to deal with latest data (and
  changes).
- Updates ingestion and dataset management to use the object store for
  metedata, avoids loading a coverage at all cost for metadata.
- Updates visualization and data product mgmt to use new format.
- Test(s)
Removes get_last_update
Fixes dmend2end tests
Merge pull request #1454 from jamie-cyber1/gevent_block2_rebase

Gevent block2 rebase
Merge pull request #1453 from lukecampbell/bounds-r2

Moves the metadata about coverages into the object store
Release Version 2.0.77
Bump Version to 2.0.78-dev
OOIION-1262: IMS forwards to DAMS for dataset agent start/stop