Added AuditObject model (w/ service) and mapped it to Objective
Client side models and workflow update for AuditObject
Migration for linking requests to objectives through audit_objects table, with model changes
Display of objectives through audit_object -- no modal support yet
Preliminary changes for request modal.  Please see comments in audit_models.js line 298
Updating migrations to show and enforce time order and support audit object type.
CORE-327 Adapted UI to allow only new Audits to be make against Constrols, while existing ones can be made against Objectives
Removed unused, unfinished compute from Request model
Fixing downgrade step so only objective requests get preserved
Migration downgrade fix and RBAC roles for AuditObject
Merge branch 'develop' into feature/control-requests

Conflicts:
	src/ggrc/assets/javascripts/models/audit_models.js
Script error on hover over object info
Update 2nd tier object info
Whitespace fixes
Merge pull request #1899 from reciprocity/feature/control-requests

CORE-327 (New) Audit Requests are mapped to Controls instead of Objectives.