In export dialog, rationalize file location, filename and title

[tedepstein]

In the plugin export dialog, the "Title" field is really the filename. It's more conventional (I think) to just choose a file location including directory and filename. But if we're going to have a filename field, let's call it filename, not Title.

[tfesenko]

The 'Title' is an API model name, I changed it to "Name" .

[daffinm]

@tfesenko Looks good to me. Done.