have the Files and Upload pages surface a 'portable_url' which uses the /static/ shorthand which is more portable across course runs
don't attempt to do URL rewriting in the import step, let the LMS/CMS runtimes do it on the fly on reference
add unit tests around asserting that /static/ links are not re-written on import
remove redudent asset_url return value when uploading files
add a test for the static url generation
alter the HTML editor so that it can do the /static/ <--> /c4x/ substitutions when toggling back and forth between the visual and advanced editors
fix cut/paste comment confusion
refactor the coffeescript a bit more. Hopefully to resolve Jasmine failures
handle cases where the 'base-asset-url' is undefined, e.g. in Jasmine tests
add jasmine tests to verify link rewriting in HTML editor
add docstring
add docstring on StaticContent utility method
Merge pull request #533 from edx/fix/cdodge/use-static-shorthand-for-asset-urls

To increase portability of courses, have the Asset Index page display the classic /static/... URL shorthand.