Remove old audit models and tables
Enable lists to use multiple sources via chained mappers

* add GGRC.ListLoaders.CrossListLoader
* remove can.Model.Cacheable.define_association_proxy and friends
* remove notes saying widgets don't contain all mapped objects
* add GGRC.Mappings with extensive, but not complete, mappings
Add audit table
Merge branch 'develop' into feature/audit
Added basic Audit support: LHN list, Program page widget with basic tree
Added "+ Objective" to sections

"+ Objective" will jump directly to create objective, and then after
successful creation, will create a join between the new objective and
the original section.
Updates for audit model, added request model, refined response model, changed LHN display for Audits to not use clickable links.
Improvements on mapping functionality

* reduce number and duplication of events due to mappings
* calculate mappings on demand rather than as observables
Trivial fix to restrict models to their proper list
Add Request object, table and service
Merge remote-tracking branch 'origin/develop' into feature/mapping

Conflicts:
	src/ggrc/assets/javascripts/apps/business_objects.js
	src/ggrc/assets/javascripts/controls/control.js
	src/ggrc/assets/javascripts/models/simple_models.js
	src/ggrc/assets/javascripts/sections/section.js
Tweaked "+ Objective" workflow

- Moved "+ Objective" link after "+ Object"
- Moved "map new objective to section" information from the form to the
title of the modal
- Added the section description as the default objective description
Added automatic date conversions for updated_at, created_at, due_on, start_on, etc.; updated Request endpoints and attributes to match server model connectivity
A few changes to avoid unnecessary events

* special case for `context`, since it's the only attribute which has
  implied meaning when `null`
* handle `context` in modals controller rather than form markup, which
  avoids repeated set, add, remove events
* add `Cycle` model, temporarily, to suppress events on Program.cycles
* don't add `_wysihtml5_mode` attribute to the instance
Fix some tree view options and bugs
Fixed if_equals not passing the proper context stack
"+ Objective" launched from the multitype selector will now use the section's description as the default
Various fixes

* don't duplicate `find_all` (and hence, `refresh`) in modals_controller
* delay rendering list items for a moment in case the controller is
  immediately replaced
* `child_count` now listens to `list.length`, which makes counts correct
Make RefreshQueue request limiting actually work
Fix case of re-adding the object just removed from the list