- Checks on MQTT topics have been made generic in the MQTTChecker singleton
class under "common"
- MQTT topic checks are now performed also when plugins are reloaded; if
the checks fail, the plugin is cleared and left uninitialized
- All sensors in a plugin not satisfying the checks are logged now, not
only the first one
- Fixed a minor bug that resulted in msgrates of 0 under certain
compilers, due to type promotion in C++