[wss] First Transform Motion

In today's teleconference, we voted on the following motion:

to redefine the transform for Signing Tokens
(see section 8.3 in draft 10 of the core) such that it
only defines how a referenced (by ds:Reference attributes
or by XPath node-set) SecurityTokenReference is dereferenced
to get the SecurityToken to be digested. The STR-transform
will no longer be used to directly reference a SecurityToken
by including a STR within the transform. The core document
will be edited as appropriate to reflect these changes.