Use differently colored turtles as a visual aid on circulation pop-ups

Use differently colored turtles as a visual aid on circulation pop-ups

Deana Cunningham of the Granville County Library System in North
Carolina asked for the turtle in the popup dialog to wear a different
color depending on whether the dialog says to route to hold shelf,
to put into transit (generically), or to put into transit for a hold.
I also handled the case of putting the copy on the (booking) reservation
hold shelf, for sites that use that.

This is the most direct possible implementation.  It's not particularly
configurable and it doesn't take accessibility into account, in that not
everyone can see the difference between red and green, etc.

Signed-off-by: Lebbeous Fogle-Weekley <lebbeous@esilibrary.com>