Bug fix - text_customization should not show in settings

Also change test to not expect text_customization
Captions are now removed from tab order when hidden
Merge pull request #1228 from edx/nick/fix-customization-visibility

Bug fix - text_customization should not show in settings
Merge pull request #1227 from edx/jkarni/hotfix/safetar

Use wrapped tar extraction
Merge branch 'release'
Merge pull request #1220 from edx/jmclaus/bugfix_bypass_captions

Captions are now removed from tab order when hidden
Refactored navigation feature

Fixed grading tests
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