Try to use libqd by default
Try to use libqd by default

We try to find and use it by default, but accept when we cannot find it.
This should match what users would expect: best effort to be fast

fplll/fplll,fplll/fplll,fplll/fplll,cr-marcstevens/fplll,fplll/fplll,cr-marcstevens/fplll,cr-marcstevens/fplll,cr-marcstevens/fplll,fplll/fplll