Initial external decorator for annotating explicit import names; Use file name as default module name in imports; Emit empty memory if there are no static segments; Update TLSF and examples accordingly

tests/compiler/class-overloading.optimized.wat

@@ -1,7 +1,7 @@
 (module
  (type $iv (func (param i32)))
  (type $v (func))
- (memory $0 1)
+ (memory $0 0)
  (export "test" (func $class-overloading/test))
  (export "memory" (memory $0))
  (start $start)