Relational.canonical simplifies Ge -> Le and Gt -> Lt

This is made part of Relational simplification and is
used in the equals method for Relationals.

The presence of Relationals in Booleans sent to equals
raises an error since that routine is not set up to handle
them.
And and Or are complementary-arg aware
Impies is complementary-arg aware
Xor is complementary-arg aware
Implies(x, x) -> true
quick