1. KList[M[_]] now instead of KList[HL <: HList, M[_]]
a. head, tail work properly in this variant
b. disadvantage is that full type not easily transformed to new type constructor
2. AList abstracts on K[L[x]], a higher order type constructor.
A. Instances written for:
a. KList
b. Seq[M[T]] for a fixed T
c. TupleN
d. single values
e. operate on one type constructor when nested
B. Main disadvantage is type inference. It just doesn't happen for K[L[x]].
This is mitigated by AList being used internally and rarely needing to construct a K.
Mark Harrah