Make sure isconnected() works with struct variables.

(1) At runtime, when resolving isconnected(), for a struct, recurse into the first
    field of the struct (recursively, if that, too, is a struct) and figure out
    whether that is connected.

(2) At oslc time, to make sure this happens properly as we descend into functions,
    we have to be sure to correctly alias the formal params to actual params
    for structs as well as non-structs.