Several changes to help with adding 64bit support.

* Change osx to osx32
* Change win to win32
* Change defaults from ['osx', 'win'] to ['osx32', 'osx64', 'win32', 'win64']
* Tried to hit some checks I missed.
* Change osx.json to osx32.json and win.json to win32.json
* Got failing tests down to 5....

I'm not really familiar with node unit testing, so I'm unsure how to
handle the rest of these failures.
There is no `win64` platform ([see here](http://nodejs.org/api/process.html#process_process_platform))... This needs to be changed to
```js
case 'win32':
    return process.arch === 'x64' ? 'win64' : 'win32';
```