Qt device update

[...]

     o	dev.interactive() regards devices with the displaylist enabled
 	as interactive, and packages can register the names of their
 	devices as interactive via deviceIsInteractive().

Thanks. A related issue: 2.5.0's NEWS has:

    o   options(device = ) now accepts a function object as well as
        the name of a function.

(For some reason, I had thought this was true all along, but in any
case) This means that it's now reasonable to do

options(device = function() x11("", 4, 4))

But then I get (iff there is no device open)

example(glm)

Error in match(x, table, nomatch = 0) : 'match' requires vector arguments

because dev.interactive() doesn't know about the change yet.
dev.interactive() cannot really do anything useful in this case, but
an error seems too harsh (especially since example(glm) doesn't even
have any graphics).

-Deepayan