WIP: Got significantly further after meeting with Manuel.  Inline consEnv to reveal more structure to the typechecker.
WIP: add newtypes for Sealed Exp and OpenExp
Refactor: introduce newtypes for sealed exps
Victory: The simple ELet tests succesfully converts!
DynamicAcc: Remove cruft and finish up Cond and constants
Add alternative DynamicAcc approach.  Use 'Smart' HOAS representation rather than going straight to the De-bruijn based AST
Get Map working.  VERY painful.
Add the first EPrimApp case.  Completing it will be VERY long
CPP hacks to start to add more primops