added attribute lookup helper method

stdlib/ktSrc/dom/Dom.kt

@@ -95,6 +95,11 @@ fun Element.get(selector: String): List<Element> {
     return this.getElementsByTagName(selector).toElementList()
 }
 
+/** Returns the attribute value or null if its not present */
+inline fun Element?.attribute(name: String): String? {
+    return this?.getAttribute(name)
+}
+
 /** Returns the children of the element as a list */
 inline fun Element?.children(): List<Node> {
     return this?.getChildNodes().toList()

testlib/test/dom/DomBuilderTest.kt

@@ -35,6 +35,7 @@ class DomBuilderTest() : TestSupport() {
         if (grandChild != null) {
             println("got element ${grandChild.toXmlString()} with text '${grandChild.text}`")
             assertEquals("Hello World!", grandChild.text)
+            assertEquals("tiny", grandChild.attribute("class") ?: "")
         } else {
             fail("Not an Element $grandChild")
         }