Connection enhancements

[BrianGenisio]

Implements #69 and #67.

Gives two optional ways to connect to the Particle:

By Name

var byName = new Particle({
  token: process.env.PARTICLE_TOKEN,
  deviceName: process.env.PARTICLE_DEVICE_NAME || "crazy_pickle"
});

By Host/Port

var byIp = new Particle({
  host: '192.168.0.111',
  port: 48879
});

The existing mechanism (deviceId) still works:

var byId = new Particle({
  token: process.env.PARTICLE_TOKEN,
  deviceId: process.env.PARTICLE_DEVICE_ID
});

[rwaldron]

Will review tomorrow

[rwaldron]

General note about naming things that wrap Promises: "get", in JS programming terms, implies a synchronous operation, deriving meaning from the spec's [[Get]](o, p), Get(o, p), etc. The word "fetch" better describes what these functions are doing, so should be named fetchJson, fetchDeviceId and so on

[BrianGenisio]

@rwaldron Thanks for the review. Fixed.