Okay to tag alpha3 ?

[Rod Widdowson]

> I noted it at the session, I'll send a formal announce once we have any
> doc changes we need in place.

I've started an Alpha3 installation page.  I'll work on it as time allows
between now and Monday.

Meantime, if anyone else wants to add stuff please dive in, and if anyone
thinks that the format is incorrect now would be a great time to let me
know.

https://wiki.shibboleth.net/confluence/display/IDP30/Alpha3+Installation

Rod