Merge branch 'integration-develop-nr-2020w02' into 'develop-nr'

Integration develop-nr 2020 week 02

See merge request oai/openairinterface5g!751

This integration branch contains the following MRs

* MR [706] : Merging develop tag `2019.w44` into develop-nr
* MR [746] : some cppcheck fixes and also compilation warnings removal
* MR [750] : hotfix: fix value of MAX_MOBILES_PER_ENB

Also contains an hotfix for the UHD thread priority