This commit lands full ECDSA key support when using the OpenSSL
backend. Which includes:
New KEX methods:
ecdsa-sha2-nistp256, ecdsa-sha2-nistp384, ecdsa-sha2-nistp521
Can now read OpenSSL formatted ECDSA key files.
Now supports known host keys of type ecdsa-sha2-nistp256.
New curve types:
NID_X9_62_prime256v1, NID_secp384r1, NID_secp521r1
Default host key preferred ordering is now nistp256, nistp384,
nistp521, rsa, dss.
Ref: https://github.com/libssh2/libssh2/issues/41
Closes https://github.com/libssh2/libssh2/pull/206
This introduces a test suite for libssh2. It runs OpenSSH in a Docker
container because that works well on Windows (via docker-machine) as
well as Linux. Presumably it works on Mac too with docker-machine, but
I've not tested that.
Because the test suite is docker-machine aware, you can also run it
against a cloud provider, for more realistic network testing, by setting
your cloud provider as your active docker machine. The Appveyor CI setup
in this commit does that because Appveyor doesn't support docker
locally.
