X509_VERIFY_PARAM_set_hostflags is available in 1.0.2-beta2

fixes #1295
fix warnings caused by signature changes from beta1 to beta2
add OpenSSL from RHEL/CentOS 7 to testing list
Merge pull request #1296 from reaperhulk/fix-1295

X509_VERIFY_PARAM_set_hostflags is available in 1.0.2-beta2
Merge pull request #1297 from reaperhulk/update-openssl

add OpenSSL from RHEL/CentOS 7 to testing list
DH numbers
Start of OpenSSL DH backend implementation
Some actual code
more implementation
Tests pass sort of
Key exchange!
Add DHBackend stub
Add j and q params to bindings
Add TLSKeyExchange
Add some error handling
Attempt to use the KASVS vectors
Pad computed DH keys to match NIST

If you want unpadded keys (e.g. TLS) then you will need to do
key.lstrip(b"\x00") to unpad them first.
Fix for Python 3.2
Some typos
More tests