Bug .3y28507: can now use Display Names in QL

In general, they simply work if they are syntactically legal.  You can
use not-legal Display Names by enclosing them in backticks.

Along the way, changed a bunch of Thing's name-related def's to lazy
val's instead -- they should be immutable, and they're called often
enough to be worth the space.  (I think -- we'll see.)