remove css classes that hide the metadata forms in issues
    
    the issue-custom form is no longer used, custom items are now
    in the main metadata form. Also removed some referecnes to these
    classes in the javascript.
    
    the .issue-metadata-form is now hidden in the template by default,
    using the bootstrap .hidden class. In fixing this, I found an issue
    with the render_bootstrap_field macro, where it would always use the
    issue-metadata-form class if the formclass parameter was set.