MIGRATION: Add multiple selection and rationale to multiple choice embeddables
Updated models and extraction for Multiple Choice multi selection and rationale
Report UI for multiple-select and rationale on multiple choice

Attach check marks to the actual items, so teachers can then see which student choices
were correct on a multiple-select question with correct answers.
Learner Report UI for multiple-select and rationale on multiple choice
Fix bug in extracting multiple choice when only the rationale text has changed
Fix NPE when editing existing multiple choices
Default value for rationale prompt for existing multiple choices
Update run_html support for multiple choice to work with rationale changes
Fix possible NPE, update tests for rationale changes to multiple choice

The NPE might actually be test-related, but it doesn't hurt.
Merge branch 'master' into topic_au_rationale

Conflicts:
	db/schema.rb
Merge in master, revert newrelic transaction monit

* master:
  Revert "newrelic monitoring of ... posting" 4b2579
Merge 'master' HAS deploys  use topic_au_rationale

* master:
  temporary: set has deploy branches to topic_au_rationale
Merge pull request #20 from concord-consortium/topic_au_rationale

multiple choice w/ multiple select and rationale