Force IPv4 resolving

Hi @arnaud-lb!

This is more an issue than a pull-request.

There is an issue on Youtube oEmbed APIs since more than 3 weeks, that broke call from IPv6 call.
You can read the [associate issue](https://code.google.com/p/gdata-issues/issues/detail?id=6664) on Google code.

Since this is critical for me, I patched the alb-oembed lib to force IPv4 addresses resolving when there is more than one version of IP.

I drop the fix here, maybe it will interest someone, even maybe you ;)

Cheers,
Thomas.