M214003/develop

added 9 commits

• 6309b1b6...578b4c22 - 4 commits from branch develop
• 8cbde6ad - smooth9: cleanup
• a1240b1d - smooth: added support for weighting methods avg, dist, gauss
• 8debd611 - fix warning: not eliding copy on return
• bc4c502c - remapcon: scaling of variable gridbox_area failed since release 2.0.0 (bug fix)
• 85d907d4 - Added operator remapknn with k=1

Compare with previous version

merged