Add List.scanl test
Add List.scanl test

laszlopandy/core,Dandandan/core,alexiamcdonald/elm-core,rgrempel/core,simonh1000/core,Pisys/core,suryagaddipati/core,bradurani/core,krisajenkins/core,vilterp/core,ThomasWeiser/core,alexiamcdonald/elm-core,Dandandan/core,rgrempel/core,rick68/core,manleyjster/core,ThomasWeiser/core,Pisys/core,colinmccabe/core,colinmccabe/core,vilterp/core,martinos/core,suryagaddipati/core,martinos/core,eeue56/core,manleyjster/core,rick68/core,laszlopandy/core,bradurani/core,isaacsanders/core,simonh1000/core,eeue56/core,isaacsanders/core,krisajenkins/core