[hplip/f21] (4 commits) ...Merge branch 'f20' into f21

[Tim Waugh]

Summary of changes:

  b9bcaed... IEEE 1284 Device ID for HP LaserJet Color M451dn (bug #1159 (*)
  ad222e4... IEEE 1284 Device ID for HP LaserJet Professional M1132 MFP  (*)
  5204ebb... Merge branch 'f19' into f20 (*)
  6bb19f5... Merge branch 'f20' into f21

(*) This commit already existed in another branch; no separate mail sent