Implemented stream::getPosition.
Added test for correct stream position after read was called.
cons::get(Car|Cdr) now checks that the input argument is Type::Cons.
Fixed infinite recursion in reader due to use of LCPP_SCOPE_EXIT and continuations.
Be extremely careful when using LCPP_SCOPE_EXIT and continuations!!! LCPP_cont_return does NOT return immediately when LCPP_ContinuationDebug is enabled.