Returned integers do not need to be pushed in precall
Returned arguments need to be checked for type
Pass address of returned arguments
Returned arguments need not be read
Returned arguments are automatically checked as good
Do not expected returned arguments in input list
Add test method
Add default for Tensor

Use method={} argument, undocumented.
Don't forget to push creturned (that I had rmeoved!)
Add TODO and warning...