2017-09-11 RecSys v21r6p1

This version uses Gaudi v28r2, LHCb v42r6p1 and Lbcom v20r6p1 (and LCG_88 with ROOT 6.08.06)

This version is released on 2017-patches branch.

Bug fixes

[MR !707] Fix MuonID compilation warnings in clang and gcc7

[MR !738] RichFutureRecPixelAlgorithms - Add out of bounds checks
Add some additional checks to make sure no out-of-bounds read access to vectors are performed in PixelBackgroundsEstiAvHPD, related to MR LHCb!873

[MR !741] Redo MuonID change to use force=True with PrintOn, lost in a previous MR