Only do trick when enabled, check neg as well as pos NA/NaN
Merge branch '03-ISNAN' into 04
Merge branch '03-ISNAN' into 04-coerce-bind
Merge branch '03-ISNAN' into 04-dollar
Merge branch '03-ISNAN' into 04-ifloop-debug
Merge branch '03-ISNAN' into 04-relop-logic
Merge branch '03-ISNAN' into 04-subscript
Merge branch '03-ISNAN' into 04-vec-enlarge
Merge branch '03-ISNAN' into 04-vec-subset
Merge branch '03-ISNAN' into 05
Merge branch '03-ISNAN' into 05-BLAS
Merge branch '03-ISNAN' into 05-RNG
Merge branch '03-ISNAN' into 05-matprod
Merge branch '03-ISNAN' into 05-anyall
Merge branch '03-ISNAN' into 05-data-frame
Merge branch '03-ISNAN' into 05-pow
Merge branch '03-ISNAN' into 05-rowcolSums
Merge branch '03-ISNAN' into 05-sum-prod
Merge branch '03-ISNAN' into 06
Merge branch '03-ISNAN' into 05-transpose