InvalidArgumentException: The user-entered string error for external type assets

I'm sorry for not noticing this sooner, I wasn't alerted to this report via email.

Re-rolled #5 so tests can be ran.

I think the test fixture is probably wrong here. Updating test fixture to be a truly external URL.

Committed #7 and pushed to 1.0.x, since the only change from #5 was confined to a test fixture.

Thank you for your contribution, I'll be cutting a new release shortly.

Automatically closed - issue fixed for 2 weeks with no activity.