Added Filter status, refactored demo.js

Demo.js now fixed to work with the removal of callbacks. now has a 4 second timer to allow for init() callbacks to finish.

also added Filter status functions to support HAP Filter Maintenance Accessory

Stability Improvements

A lot of stability improvements. Reduced recursive callbacks and setTimeout timers. Streamlined init of module, as well as handing calls to web service. Also parallelized calls to web service, as this appears to be supported now.

Optimizations and support for multiple devices with one session

• streamlined the init of the module as well as tried to reduce the number of request.get/post to Electrolux services. This should help with startup time and responsiveness
• added support for multiple devices with one session
• randomly generates device ID each startup of the library
• added the ability to test a specific serial number in demo.js
• other fixes

Support for Frigidaire 2.0

Update to support the new Figidaire 2.0 by https://github.com/marekbrz