Cleanup ordering, improve API

js/js.libraries/src/core/javautil.kt

@@ -8,7 +8,7 @@ private val DEFAULT_LOAD_FACTOR = 0.75f
 
 library
 public trait Comparator<T> {
-    fun compare(obj1: T, obj2: T): Int;
+    public fun compare(obj1: T, obj2: T): Int;
 }
 
 library

js/js.libraries/src/core/kotlin.kt

@@ -2,9 +2,6 @@ package kotlin
 
 import java.util.*
 
-library("comparator")
-public fun comparator<T>(f : (T, T) -> Int): Comparator<T> = noImpl
-
 library
 public fun <T> array(vararg value : T): Array<T> = noImpl