Node 0.8, 0.10 and 0.11.3 support with stable nan 1.0.0

Other changes include:
* Memory leak fixes
* Parsing x509 private keys
* Removed support for OpenSSL doing the file reading as this is bad security practice and blocks the application. Files can be read in JS asynchronously and fed to the parser.

I would appreciate @kkoopa to give another look at nan usage. I need this changes for my repo http-master so I would appreciate to merge this. I am tired of using git repo as package.json dependency. :P