No longer shadow variables in first order transform.
Add setArrayDims convenience function.
Size-annotation-related fixes to enabling optimisations.
More fully check size annotations in type checker.
In enabling optimisations, also look at lambda return types.
In Rebinder, also hoist in certificates.
Also look at return type in freeInLambda.
Perform unique renaming after internalisation.
Look for free variables in types in Rebinder.
Fix shape tracking in type checker.