Scaffolding for import progress reporting
Route ajax request to appropriate view, and show feedback only then

Hook up view

Fix getStatus function
Studio: revises general layout/styling of import view and adds in detail progress feedback after import (WIP)

Studio: removes import progress bar HTML and Sass; hides import status by default

Studio: revises import file upload success copy; sets up showing/hiding states for import status and additional messages

Studio: revises iconography and adds in success step in import status feedback

Studio: adds hidden styling back into import status UI
Hook up js to css classes
Use swanky error css for error messages
Studio: revises import view Sass extends to use placeholder syntax
Remove references to old upload progress bar
Re-add bar references
Studio: adds in action-related elements to the status display UI of the Import view
Studio: copy and styling changes to import view to support new status UI
Clear import status on retry
Review fixes

Studio: revises import help/status copy to better reflect/generalize what is done with imported content

Add test cases for import status
Move import-related js to import.js
Update changelog
Studio: adds in instructional copy to user on when it is safe to leave the import view without harming an import process
disable buttons for large courses on legacy and beta instr dash

set max enrollment for downloads to 200
LMS: abstracts consistent message/copy color styling from Instructor Dashboard view

LMS: adds message styling to the separate instructor_2 Sass file
add entry to changelog
Merge pull request #1232 from edx/will/navigation-grading-test-fixes

Fix navigation and grading acceptance tests
Merge pull request #1125 from edx/adam/remove-instr-dash-buttons

disable buttons for legacy and beta instr dash