* 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
Introduce DEFAULT_BUFFER_SIZE for StatefulService related classes
Add configurable buffer sizes for StatefulService related classes
Remove redundant function from HttpEndpoint
* 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
