Bug Fix: Missing Datacenter from context

- Datacenter is specified via the Configuration and set to Deuce Context
Bug Fix

- Datacenter must be all lowercase as that is how it is compared; better to do this once when we load it from the config than every time we compare
- Added tests for Deuce Context to validate that it works, and validate that it properly handles the datacenter regardless of how user enters it in config
Updates to validations. jsonschema
Updates to diagnostic tests
feat: delete blockstorage endpoint

- Allows to delete a block directly from block storage, if it exists and
  zero references. returns a HTTP 204

- If the block has references, returns HTTP 409

- If the block doesnt exist we return a 404

Bugfix Cassandra driver:

Changed up timestamp for reftime to be actually UTC, since Cassandra's
timestamp is a local timestamp along with a UTC offset like: -0400
Merge pull request #186 from BenjamenMeyer/bugfix_context_datacenter

Bug Fix: Missing Datacenter from context
bugfix: DO NOT delete blocks with zero references

i.e x-reference-count of 0, but still exisiting in metadata.
Merge pull request #187 from jc7998/schema_validation

API Tests: Changes to status code validations and added jsonschema validation
Merge pull request #166 from BenjamenMeyer/enhancement_block_storage_controller_get_object

Block Storage: Get Block
Merge remote-tracking branch 'upstream/master' into delete_blockstorage_endpoint

Conflicts:
	deuce/model/blockstorage.py
	deuce/tests/test_blockstorage.py
pep8: fix
Merge pull request #189 from TheSriram/delete_blockstorage_endpoint

feat: delete blockstorage endpoint
Merge branch 'master' into enhancement_block_storage_controller_head_object