Mapping vars before setting in environment using function nubByLastVar.
Added function nubByLastVar that yields a Data.Map from a list and the returns back an ordered list of type [(String), (String)]. If the list contains more than one value for the same key, the last value for the key is retained.
nubByLastVar.nubByLastVarthat yields aData.Mapfrom a list and the returns back an ordered list of type[(String), (String)]. If the list contains more than one value for the same key, the last value for the key is retained.