Merge pull request #662 from public/fix-interface-more

Remove backend arg from the backend interface
Bind X509 attribute methods for EVP_PKEYs
PKCS8 bindings that let you specify the encryption
Merge pull request #666 from public/pkcs8-bindings

PKCS8 bindings that let you specify the encryption
Merge pull request #665 from public/evp-pkey-attributes

Bind X509 attribute methods for EVP_PKEYs
Style nit
Merge pull request #668 from alex/style-nit

Style nit
0.2.1 changelog
Merge pull request #671 from reaperhulk/0.2.1-changelog

0.2.1 changelog