Re-created styling for AI-XML authoring
Preserve the assessment order in the Studio editor.

Conflicts:
	openassessment/xblock/static/js/openassessment-studio.min.js
Reverted to some of the old logic now that we are not using codemirror
Changed the call mechanism from examples to examples_xml to differentiate for validation
Merge branch 'authoring' of https://github.com/edx/edx-ora2 into grady/ai-authoring

Conflicts:
	openassessment/xblock/defaults.py
	openassessment/xblock/static/css/openassessment.css
	openassessment/xblock/static/js/openassessment-studio.min.js
	openassessment/xblock/studio_mixin.py
	openassessment/xblock/test/data/invalid_update_xblock.json
	openassessment/xblock/test/data/update_xblock.json
	openassessment/xblock/test/test_studio.py
Merge pull request #522 from edx/grady/ai-authoring

Grady/ai authoring