Finished renaming type variables in Checked.
Implemented Compose-like type which keeps track of nesting of functors in the type via GADTs -- this will enable us to avoid the use of such things as OverlappingInstances and make more elegance happen in general.
Migrated from Compose-based model to one based off a custom Nested GADT, which allows cleaner type specification of many, many things, and allows us also to avoid Overlapping Instances.
Made Checked support the inclusion of arbitrary functions, tagged as such. Pretty sure at this point that Checked is going to be a dead-end, because I don't think you can give a checked evaluation function the same asymptotic speed as an unchecked one.