Refactor app. config. behavior to use third-party library (https://github.com/lorenwest/node-config).
Update README related to new config. setup.
Merge pull request #14 from williambogaiv/config-refactor

Refactor app. config. behavior to use third-party library
Fix default light provider so it uses raspi instead of fake provider.
Previous logic was backwards in terms of forcing the config. to define the raspi provider.
The expected behavior is to for the fake provider for dev. purposes.
Merge pull request #15 from williambogaiv/fix-default-light-provider

Fix default light provider