[Openid-specs-fapi] Issue #75: Support other method of HoK than TOKB (openid/fapi)

[Nat Sakimura]

New issue 75: Support other method of HoK than TOKB
https://bitbucket.org/openid/fapi/issues/75/support-other-method-of-hok-than-tokb

Nat Sakimura:

There are cases that you want to have other way of HoK than TOKB, e.g., In a platform that cannot support Token Binding, or when TLS is terminated before the OAuth server. 

So, only HoK should be required and not TOKB. TOKB should be made into an option to support HoK.

Responsible: Nat