Make sure button has a dedicated space at the left of tutorialBox.
Fix delete button issues by calling removeListener() instead of clearListeners().
Create error module.
Modify instructions sidebar on /start page.
Add mapUserError CustomEvent to error module.  Add to standardCurriculum in tutorial.
Merge branch 'master' into production

Conflicts:
	core.js
	css/style.css
	css/style.less