Eliminate uninitialized value warnings in Report.pm.
(grafted from 618a73a59bacab3358a814fc7448e2cb7d5d5ec5)

--HG--
extra : source : 618a73a59bacab3358a814fc7448e2cb7d5d5ec5
Eliminate code generating uninitialized values warnings relating to #1116.
  To be reinstated later.
(grafted from cb3342fb3c133de96becd5d638dac5df8e29e8fe)

--HG--
extra : source : cb3342fb3c133de96becd5d638dac5df8e29e8fe
Fix issue #1111 (and potentially lots of others) due to PGNumber not
evaluating to false, even for zero-values.
(grafted from dbad648a2c1f905a4bd6da816f768dc21635c0e0)

--HG--
extra : source : dbad648a2c1f905a4bd6da816f768dc21635c0e0