Documentation and dependencies for v42r7 release

ReleaseNotes/v42r7.md

+2017-12-12 DaVinci v42r7
+========================
+
+Release for 2017 re-stripping campaign S29r2
+--------------------------------------------
+
+This version is released on the 2017-patches branch.
+It is based on Gaudi v28r2, LHCb v42r6p1, Rec v21r6p1, Phys v23r7, Analysis v18r6 and Stripping v11r5.
+Uses LCG_88 with ROOT 6.08.06.
+
+- Added StrippingCache and DaVinciTests for S29r2.
+  - See merge request lhcb/DaVinci!128
+- Validate DaVinci configuration for Turbo data.
+  - See merge request lhcb/DaVinci!116
+- DaVinci config: Set "CondDB(Upgdade=True)" for DataType='Upgrade'.
+  - See merge request !113
+- Fix untested StatusCodes exposed by gaudi/Gaudi!386.
+  - See merge request !110