Bug 1136: async load module clobbers module handler

In cajita-module, xhrAsyncLoad creates a stub module handler which
is missing a lot of methods.

Specifically, it is missing handleUncaughtException which means that
if a module throws an exception, then onload handlers will never fire.


Submitted @3776

[ihab.awad, 2009-10-03 03:10:53]

LGTM

Thanks for all the diverse and sundry cleanups.