fix #10 KDF.Complexity derivation functions now require salt

src/commonTest/kotlin/KeysTest.kt

@@ -442,7 +442,7 @@ class KeysTest {
         assertContentEquals(k2.keyBytes, k2.id.id.body)
 
         val k7 = SymmetricKey.new()
-        val k8 = KDF.Complexity.Interactive.derive("super")
+        val k8 = KDF.Complexity.Interactive.derive("super", KDF.Argon.randomSalt())
 
         fun testToString(k: UniversalKey) {
             val s = k.toString()