Fix status code and styling issues for
server-side handling of large file uploads.
Add UPLOAD_CHUNK_SIZE_IN_MB settings constant for 
the front-end, and improve commenting for these 
constants.
Revert whitespace changes
Standardize variable names across front/backend.

- Note: also fix an i18n issue with format string
for upload modal
Move Notification from main.coffee to assets.js. 

Reverted main.coffee
Remove unused constant
Move clean_large_asset to tearDown function
Add override for asset limit constants for tests.