export additional test function (at package level).

This is so you can run the tests with ASDF, I think. It was something
I did whilst SLIME was a bit messes-up and I was a bit desperate with
trying to fix it. So, I don't know if this additional exported
function is needed. Everything seems to work with it still there --
after I restarted Emacs and SLIME -- so I'm keeping it like this for now.

tests/package.lisp

@@ -1,6 +1,7 @@
-;;;; package.lisp
+;;;; tests/package.lisp
 
 (defpackage #:ritherdon-rest-tests
   (:use #:cl #:fiveam)
   (:export #:run!
-	   #:all-tests))
+	   #:all-tests
+	   #:test-quasi))