Merge pull request #854 from lukecampbell/stored_value_transform

Stored value transform
Fix instrument agent test yet again
Merge branch 'master' of github.com:ooici/coi-services
Merge pull request #855 from shenrie/master

Fix instrument agent test yet again
Add driver shutdown on quit.
Fix driver shutdown on quit.
Release Version 2.0.18
Bump Version to 2.0.19-dev
Adds reference attachment support (with test)
Adds cleanup to test and bumps submodule references
Merge pull request #856 from lukecampbell/attachments

Attachment Reference Support
Updates test, support for multiple attachments
Merge pull request #857 from lukecampbell/attachments

Updates test, support for multiple attachments
Work on attachment walkthrough

Conflicts:
	extern/ion-definitions
	ion/services/sa/acquisition/data_acquisition_management_service.py