split the filter method into filter(predicate) and filterTo(result, predicate) for easier completion & avoid confusion - seems 2 methods is better than the default arguments approach

testlib/test/CollectionTest.kt

@@ -67,7 +67,7 @@ class CollectionTest() : TestSupport() {
 
     fun testFilterIntoLinkedList() {
         // TODO would be nice to avoid the <String>
-        val foo = data.filter(linkedList<String>()){it.startsWith("f")}
+        val foo = data.filterTo(linkedList<String>()){it.startsWith("f")}
 
         assertTrue {
             foo.all{it.startsWith("f")}
@@ -82,7 +82,7 @@ class CollectionTest() : TestSupport() {
 
     fun testFilterIntoSortedSet() {
         // TODO would be nice to avoid the <String>
-        val foo = data.filter(hashSet<String>()){it.startsWith("f")}
+        val foo = data.filterTo(hashSet<String>()){it.startsWith("f")}
 
         assertTrue {
             foo.all{it.startsWith("f")}