Fixed issue 2

- Redesigned cookbook to follow the multi-platform pattern that the Python cookbook uses
- Deprecated all install_from_* recipes
- Merged Windows and *nix attributes where possible
Added ChefSpec tests

Default and Windows recipes now have ChefSpec tests that will run on x64 Windows.
Fixed build

Install_method now selects which recipe to run, so defaulting it to binary for Windows was wrong.
Fixed cookbook version checking on Windows

Cookbook was creating incorrect path to nodejs.exe on 64bit versions of Windows under 32bit ruby and wasn't correctly escaping a path with spaces.

Added ChefSpec tests to the helper class and refactored to allow for testing.
Packaged NodeJS build get installed to /usr/bin
Merge pull request #3 from daptiv/fix-issue-2

Fix issue 2