* Add framework for built-time feature selection
* Allow MQTT, NTP, OTA features to be disabled at build time
* Allow Project screens to be disabled at build time
* Allow security features to be disabled at build time
* Switch to std::function for StatefulService function aliases for greater flexibility
* Bump various UI lib versions
* Update docs
* Rename "serialize" and "deserialize" functions to "read" and "update" to reflect API in StatefulService
* Move new definitions to StatefulService.h so it is obvious it is not general purpose
* Update README
* Update back end to add MQTT and WebSocket support
* Update demo project to demonstrate MQTT and WebSockets
* Update documentation to describe newly added and modified functionallity
* Introduce separate MQTT pub/sub, HTTP get/post and WebSocket rx/tx classes
* Significant reanaming - more accurate class names
* Use PROGMEM_WWW as default
* Update README documenting PROGMEM_WWW as default
* Update README with API changes
Adds a webpack plugin to package interface as PROGMEM into a header file in the framework.
Adds a build flag to optionally enable serving from PROGMEM or SPIFFS as required
Adds documentation changes to describe changes
