update package.json to reference nan 2.x
update package.json to reference nan 2.x

Reviewed-By: da39a3ee5e6b4b0d3255bfef95601890afd80709@kunalspathak

munyirik/node-uwp,Microsoft/node-uwp,jianchun/node-uwp,jianchun/node-uwp,Microsoft/node-uwp,munyirik/node-uwp,jianchun/node-uwp,munyirik/node-uwp,Microsoft/node-uwp