Unlike the Scoped* types, bssl::UniquePtr is available to C++ users, and
offered for a large variety of types.  The 'extern "C++"' trick is used
to make the C++ bits digestible to C callers that wrap header files in
'extern "C"'.

Change-Id: Ifbca4c2997d6628e33028c7d7620c72aff0f862e
Reviewed-on: https://boringssl-review.googlesource.com/10521
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>

This and the following commits will import NIST's ECC test vectors.
Right now all our tests pass if I make P-224 act like P-521, which is
kind of embarrassing. (Other curves are actually tested, but only
because runner.go tests them against BoGo.)

Change-Id: Id0b20451ebd5f10f1d09765a810ad140bea28fa0
Reviewed-on: https://boringssl-review.googlesource.com/10700
Commit-Queue: David Benjamin <davidben@google.com>
Commit-Queue: Adam Langley <agl@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>