Add missing libs to js_libs.

Fix JsAstUtil using wrong Nullable annotation.

.idea/libraries/js_libs.xml

@@ -3,6 +3,9 @@
     <CLASSES>
       <root url="jar://$PROJECT_DIR$/js/js.translator/lib/js.jar!/" />
       <root url="jar://$PROJECT_DIR$/js/js.translator/lib/dartc.jar!/" />
+      <root url="jar://$PROJECT_DIR$/js/js.translator/lib/args4j-2.0.12.jar!/" />
+      <root url="jar://$PROJECT_DIR$/js/js.translator/lib/guava-10.0.1.jar!/" />
+      <root url="jar://$PROJECT_DIR$/js/js.translator/lib/json.jar!/" />
     </CLASSES>
     <JAVADOC />
     <SOURCES>

js/js.translator/src/org/jetbrains/k2js/translate/utils/JsAstUtils.java

@@ -19,8 +19,8 @@ package org.jetbrains.k2js.translate.utils;
 import com.google.common.collect.Lists;
 import com.google.dart.compiler.backend.js.ast.*;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
-import javax.annotation.Nullable;
 import java.util.Arrays;
 import java.util.Iterator;
 import java.util.LinkedList;