Add tests for incorrect number of arguments to readers, writers and accessors
Checks zero and two argument calls for the readers. Checks zero, one and three argument calls for the writers and accessors. Currently I have SBCL failing the three argument calls for the writers and accessors because they allow 2 or more arguments. Clasp passes all. I haven't investigated other implementations yet.
Please note that 7.5.2 suggests that the writers should take only two arguments.
Resolves #29 (closed)