Improve injector interface

Improve injector interface

Make the injector's mode button lag-resistant.  Display the mode on
the button, as is done with other machines' toggle buttons.  Describe
the modes using the same words that are now used to distinguish the
corresponding pipeworks objects.  Expand name to "self-contained
injector", now that the pipeworks objects are also called "injector".
Show injector item image along with the item name at the head of the form.