Do not report NO_CLASS_OBJECT when namespacesAllowed=true

Now with nested classes the expression "A.something" makes sense even when A
doesn't have a class object ("something" could be a nested class)

Also "A" expression now gets a NamespaceType with the scope of all static
nested classes of A

 #KT-1174 In Progress

idea/testData/checker/ClassObjects.kt

@@ -20,7 +20,7 @@ object b {
 }
 
 val a = A.x
-val c = <error>B</error>.x
+val c = B.<error>x</error>
 val d = b.<error>x</error>
 
 val s = <error>System</error>  // error