Fix compiling on latest node

I have fixed compiling on latest node so this fixes issue #8 but there is still problem with running ...

`node: symbol lookup error: node-x509/build/Release/x509.node: undefined symbol: BIO_s_file`

It works properly on node 0.11.4 and broke on node 0.11.5. I have contacted Fedor Indutny for some insight as he was the one making openssl changes in node.