Update show.php

Removed IF-elseif statement for category features - weren't working - replaced with simple IFs around each feature.
Trying different formatting for the first few aerophone features, to see if like it better.
Reformatted layout for Continent-Region-Nation-Formation, per Roger, also surrounded with IFs so they hide if empty.
Switched metadata field for designating Manufacturer, was "Creator" but that entered into Item Citation which wasn't desired, so changed to "Publisher".