Allow passing arguments through to the SerialPort constructor. Closes gh-64

Based on the original patch by @achingbrain here https://github.com/jgautier/firmata/pull/64. That patch had long bitrotted beyond use, but the feature is still relevant.
SERVO_CONFIG sysex command support.
v0.3.4
Use object-assign module instead of es6-shim

This corrects an issue running firmata inside of a Chrome App, where es6-shim
conflicted with Chrome's CSP.

Specifically, this line was the culprit:
https://github.com/paulmillr/es6-shim/blob/master/es6-shim.js#L72

If in the future more ES6 methods are used, another solution might be found (or
a patch submitted to es6-shims).
Merge pull request #76 from hybridgroup/master

Use object-assign module as replacement for es6-shim
v0.3.5
Ensure that the capabilities reponse operation is idempotent. Fixes gh-79
Replace ^ with ~
Add 1-wire api docs
v0.3.6
Should have a name property of "Firmata". Fixes gh-82