Windows support

While the node-bluetooth-serial port project currently supports OS X and Linux, I decided to extend support so that it works with Windows XP and above too. The intent of this is to be able to re-use and extend the library cross platforms and versions of each OS. Therefore, you will notice that I have not used any of the new windows API's. I tried to keep the implementation as close to the Linux version as possible (regarding the design and API's) with the intent to simplify readability and therefore understanding which leads to enhancing maintainability through the previously defined code patterns. As a point in hand, it was exciting and fun getting this to work and contributing back.