using nan (https://github.com/rvagg/nan) to support virtually all node version

Using nan, Native Abstractions for Node.js (https://github.com/rvagg/nan) to support virtual all node version, especially node 0.11.

I double checked that this commit passes build on both node 0.10.32 and node 0.11.14.

Addressing issue https://github.com/brainling/cpuid-node/issues/2