Fixes #30. Fix test for data-saving, add data-saving='false' on init

Fixes https://github.com/owncloud/files_texteditor/issues/30

@jancborchardt @labkode

To test: make some changes, press Ctrl+s (or equiv on mac), make more changes, use Ctrl+s again.

Previous: Would not save the second time.
Now: Saving should work more than once with the shortcut.