Endpoint resolution

[Cantor, Scott]

I checked in flow changes to include endpoint checking/resolution into the
SAML 1 test flow, I haven't touched the SAML 2 testbed flow yet.

Most of the redundancy in the InitializeOutboundMessageContext action is
gone, the signing parameters piece is still there for now.

Tom, you can review to make sure this is what you expected.

Brent, I added a saml-binding-config.xml Spring file in idp-conf in "user"
space where the lists of outgoing bindings are laid out. I'm still
thinking we could use this for encoder lookup, maybe by extending the
OpenSAML BindingDescriptor class with a Spring version that adds a bean ID
to use for the encoder. My concern is just the work of defining the
bindings multiple places if we keep the two uses separate
(ordering/enabling them vs. encoder lookup).

-- Scott