This change implements support for the extended master secret. See
https://tools.ietf.org/html/draft-ietf-tls-session-hash-01
https://secure-resumption.com/

Change-Id: Ifc7327763149ab0894b4f1d48cdc35e0f1093b93
Reviewed-on: https://boringssl-review.googlesource.com/1930
Reviewed-by: David Benjamin <davidben@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>

Change-Id: Ia349c7a7cdcfd49965cd0c4d6cf81a76fbffb696
Reviewed-on: https://boringssl-review.googlesource.com/1604
Reviewed-by: Adam Langley <agl@google.com>

Some test code to insert a bogus session ticket was retained. Also,
decryptTicket mutated its input, in turn, mutating the ClientHello,
breaking the Finished hash.

The latter fix should probably be merged upstream.

Change-Id: I6949f842c67e19df8742561fb0b849af9f5f099d
Reviewed-on: https://boringssl-review.googlesource.com/1290
Reviewed-by: Adam Langley <agl@google.com>

Initial fork from f2d678e6e8 (1.0.2 beta).

(This change contains substantial changes from the original and
effectively starts a new history.)