Remove the Type constraint from infoRange
Fold singleton ranges into literals

Fix for #27.
Add an (almost) untyped middle-end.
Add a couple of type signatures and remove an identity function.
Add Bits to PrimOps.
Add Sel to Primops.
Add Conversion to PrimOps.
Add Num and Ord to Primops.
Fix SourceInfo.
Add Logic to Primops.
Add Floating to Primops.
Remove unused includes.
Add Complex to Primops.
Add Eq and Error to Primops.
Add Integral to Primops.
Add Array to Primops.
Add Save, SizeProp, SourceInfo and Switch to Primops.
Add Run and Return to Primops.
Improve size propagation for untypeType.
Add LoopM and Mutable to Primops.