* added support for secure TLS connections
on ESP32 and ESP8266 close#101
* added TLS test builds
* added documentation for TLS
fixed some some issues in the documentation
* added documentation for error code=54
* Automatically set mqtt buffer size
Current versions of pubsubclient allows the buffer size to be set
dynamically: https://github.com/knolleary/pubsubclient/pull/282
We can take advantage of this to avoid having to modify one of the
dependencies and instead automatically up the buffer size when a
powerful board is detected.
Florian