Added clarification of the distinction between FoldableConstantType and LiteralType.
Added clarification of the distinction between FoldableConstantType and LiteralType.

lrytz/scala,lrytz/scala,scala/scala,scala/scala,lrytz/scala,scala/scala,lrytz/scala,martijnhoekstra/scala,martijnhoekstra/scala,lrytz/scala,scala/scala,scala/scala,martijnhoekstra/scala,martijnhoekstra/scala,scala/scala,martijnhoekstra/scala,lrytz/scala,martijnhoekstra/scala