Incremental improvements

Most notably, this adds an option to change the default name of uploaded files. This enables the user to have an upload form without an input box for the file title. Previously in this scenario all uploaded files would be named "Unnamed". Now this default file name can be changed to any fixed value in the settings or (and this is the more useful feature) the original file name of the uploaded file can be used.

See the commit log for more details on the other minor fixes in this pull request.