plan for send certs?

[detailyang]

hello.
This project is awesome to implement some thing about ocsp:)
@indutny do you have plan to complete your send certs? for ocsp response.
now we do not send certs on ocsp response, so always get the output when using openssl to test as following:

routines:OCSP_basic_verify:signer certificate not found.

never mind, now it's enough good even if do not send certs:)