Add tasks for all the new languages

Task/Arithmetic-Complex/LFE/arithmetic-complex-4.lfe

@@ -0,0 +1,11 @@
+(defun new (r i)
+  (make-complex real r img i))
+
+(defun modulus (cmplx)
+  (mult cmplx (conj cmplx)))
+
+(defun div (c1 c2)
+   (let* ((denom (complex-real (modulus c2)))
+          (c3 (mult c1 (conj c2))))
+     (new (/ (complex-real c3) denom)
+          (/ (complex-img c3) denom)))))