Text Annotation Tool: Added Instructor Filter and Clear Search

Video Annotation Tool: Added Instructor Filter

Image Annotation Tool: Added Instructor Filter

Image Annotation Tool: Annotation Mode for AB Testing

Annotation Tools PR Fixes

- forgot to overwrite the previous line

Annotation Tools: PR Fixes

- Fixed camel case for variable name
- Fixed indentation in imageannotation.html
- Changed all mentions of Instructor Username to Email
- Turned annotation_mode into phrase
- Fixed indentation in imageannotation.html
- Added comments in imageannotation.html

- Changing annotation_mode in OSDA

Annotator Tools: OpaqueKeys update for Notes

Annotation Tools: Added CommonAnnotatorMixin

Annotator Tool: Fixed delete bug and factored out settings

Removed print context

Conflicts:
	common/lib/xmodule/xmodule/imageannotation_module.py
	common/lib/xmodule/xmodule/textannotation_module.py
	common/lib/xmodule/xmodule/videoannotation_module.py
	lms/djangoapps/notes/views.py