Add assignment writer
Update __init__.py
Add id field in assignment toolbar
Update create assignment example
Fix css
Fix case when there are no headings
Rename ReleasePreprocessor to AssignmentPreprocessor
Deprecate points in heading cells
Save out rubric file
Update create assignment example
Add title traitlet to assignment preprocessor
Merge branch 'use-problem-ids'
Add page on creating an assignment
Add docs index page
Add release and solution versions doc
Remove readme for create assignment example
Add docs about points and the %run_solutions magic
Update docs to include stuff about assignment writer and cell ids