Bug 1362119 - part 1 - Moving dom/base/Script{Loader,Element}.* in dom/script, r=ehsan

This patch does these things:

1. it moves nsScriptElement, nsScriptLoader, ScriptSettings, nsIScriptElement
   and nsIScriptLoaderObserver in dom/script
2. it renames nsScriptElement to mozilla::dom::ScriptElement
3. it renames nsScriptLaoder to mozilla::dom::ScriptLoader

dom/html/HTMLScriptElement.cpp

@@ -38,7 +38,7 @@ HTMLScriptElement::WrapNode(JSContext *aCx, JS::Handle<JSObject*> aGivenProto)
 HTMLScriptElement::HTMLScriptElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo,
                                      FromParser aFromParser)
   : nsGenericHTMLElement(aNodeInfo)
-  , nsScriptElement(aFromParser)
+  , ScriptElement(aFromParser)
 {
   AddMutationObserver(this);
 }