Fix crash when importing CSV from a URL [#135372347]
Fix crash when importing CSV from a URL [#135372347]

The AppController.openDocumentFromUrl() method was removed along with other I/O code in a recent cleanup. It was still being used to handle the case of importing CSV from a URL, however. With this commit, we restore that functionality in the form of the AppController.importTextFromUrl() method.

concord-consortium/codap,concord-consortium/codap,concord-consortium/codap,concord-consortium/codap,concord-consortium/codap