Get static methods fully working.

They are compiled as local variables defined in an implicit
scope surrounding the class. This has the right semantics and,
better, means that there's no VM support needed for them.

They're purely syntax sugar.

test/constructor/default.wren

@@ -6,3 +6,6 @@ class Foo {
 var foo = new Foo
 IO.print(foo is Foo) // expect: true
 IO.print(foo.toString) // expect: Foo
+
+// TODO: Get rid of this. If you're defining a class, it's because you have
+// some state to initialize. if you don't, it shouldn't be a class.