add java.util.Map's size and empty properties

stdlib/ktSrc/JavaUtilMap.kt

@@ -1,20 +1,16 @@
 package std.util
 
-import java.util.*
+import java.util.Map as JMap
 
 // Map APIs
 
 /** Returns the size of the map */
-/* TODO get redeclaration errors
-val Map<*,*>.size : Int
+val JMap<*,*>.size : Int
     get() = size()
-*/
 
 /** Returns true if this map is empty */
-/* TODO get redeclaration errors
-val Map<*,*>.empty : Boolean
+val JMap<*,*>.empty : Boolean
     get() = isEmpty()
-*/
 
 /** Returns the value for the given key or returns the result of the defaultValue function if there was no entry for the given key */
 inline fun <K,V> java.util.Map<K,V>.getOrElse(key: K, defaultValue: ()-> V) : V {