Update node-js implementation with device and os objects

[Krinkle]

Currently output contains:

{
  family:
  major:
  minor:
  patch:
  os:
}

Would be nice to have device, isMobile and isSpider in there as well (like some other implementations do).

Basically to add:

os.family
os.major
os.minor
device.family
device.isMobile
device.isSpider

[shripadk]

Oh I forgot to add os.major, os.minor. Will do so now.

[tobie]

Fixed in #91 which I'd love your feedback on.