Copy Layout

We would implement a new button on the Layout List that would appear alongside the current "Design, Edit and Delete" buttons. This new button would be called "Copy". Pressing the button would bring up a new form which asked for a new layout name. The copy functionality would duplicate the layout to be copied, link all the existing media and permissions. The only difference would be the new name.

Notes:
 * It would not attempt to copy any of the scheduling information.
 * After copying there would be no link between the two layouts.

The functionality is slightly more complex than it appears due to the media links being stored in the Layout XML (Xibo Layout Format - XLF). This means that the copy function would have to parse the XLF and create new link records to all media assigned to that layout.