Issue2191 :: Media Editor Take Photo Not Working

Fix [Issue 2191](https://code.google.com/p/ankidroid/issues/detail?id=2191), we weren't specifying a publicly writable directory. Please merge PR #458 first, and its commits should disappear.
AndroidManifest.xml:258: Error: Class referenced in the manifest, com.ichi2.anki.multimediacard.activity.MultimediaCardEditorActivity, was not found in the project or the libraries [MissingRegistered]