Annotation Tools: Add helper functions and fixed pep8/pylint errors

Small plugin fixes
Image Annotation Tool: create xmodule and install js files
Image Annotation Tool: Add static images for openseadragon navigation
Image Annotation Tool Fixes
- Added component to view

- Added correct images for OSD

- Fixed path to codemirror

- Tinymce fullscreen works now

- Pep8/Pylint Fixes

- Default image changed and added call to super
Image Annotation Tool: Add linkback functionality to image thumbnails

Changes requested in PR