R1:af295e0b2620

OAuth Server enhancements -- more complete access token response and groundwork
for scope

Summary:
this patch makes the access token response "complete" relative to spec by
returning when it expires AND that the token_type is in fact 'Bearer'.

This patch also lays the groundwork for scope by fixing the underlying data
model and adding the first scope checks for "offline_access" relative to expires
and the "whoami" method. Further, conduit is augmented to open up individual
methods for access via OAuth…