+hash salt derivation for any size. better naming

src/commonTest/kotlin/PBKDTest.kt

@@ -33,7 +33,7 @@ class PBKDTest {
             assertEquals(i.kdp, kx.id.kdp)
 
         }
-        val (y1,y2,y3) = k1.id.kdp!!.kdf.deriveMultiple("foobar", 3)
+        val (y1,y2,y3) = k1.id.kdp!!.kdf.deriveMultipleKeys("foobar", 3)
         for( (a,b) in listOf(y1,y2,y3).zip(listOf(k1,k2,k3))) {
             assertEquals(a,b)
             assertNotNull(a.id.kdp)