Test.

Added a function with a failing test for full house. Really
hoping that this implementation will be real simple given
that I've built so many helper functions already.
Implementation.

Added an implementation for full-house-p. It is fairly simple
and straightforward but I'm starting to feel that all of
these remove-if's should perhaps be moved into a helper
function instead.
Test.

Added some more tests to full-house-p and the last one fails
unexpectedly. The hand 2S 2H 2D 2C 3S *should* return nil but
returns 2.
Implementation.

Fixed the bug that caused the last test to fail. The return-
from was outside the when-expression.