Import post demo fix

Few fixes post demo
 * https://trac.openmicroscopy.org.uk/ome/ticket/10980
 * https://trac.openmicroscopy.org.uk/ome/ticket/10982
 * https://trac.openmicroscopy.org.uk/ome/ticket/10977
 * https://trac.openmicroscopy.org.uk/ome/ticket/10981
 * https://trac.openmicroscopy.org.uk/ome/ticket/10985
 * https://trac.openmicroscopy.org.uk/ome/ticket/10984

Some tickets are "clean up"

To Test:
 * Make sure the green tick/red cross and the menu are displayed as soon as the import is complete
 * Check that the order of the controls (i.e. Retry All etc)
 * Folder import w/o valid candidates
 * Cancel folder import, files import, using cancel button and cancel All(see https://trac.openmicroscopy.org.uk/ome/ticket/10984)
 * Check new layout (cf. mockup)