add test for evalSHA for a script that returns a numeric
make evalSHA work with scripts that return numeric

This isn't a very nice solution, parses using the asAny aggregate then cases to the type parameter.
Still, as it's a completely untyped operation, there's no compiler help available here even in
principle, so it's in. Definitely interested to hear of better ways to do this.
Merge branch 'joekearney-non-string-eval-return'
Merge eval changes from @joekearney