Changes to handle conflict with monitoring: 1. we check if counters are already running, and just read them if this is the case. 2. we program them if they are not running. 3. When dcdb stops, they are left running for other agents like EAR.

-check if counters already enabled before programming them
-reset counters if stopped

- Implemented a check in MQTTPusher that prevents the main publish
loop from being invoked anytime mosquitto_loop returns, but only once
every second at most

- Values for MaxInflightMsgNum and MaxQueuedMsgNum are now logged at
startup

- Checking for invalid sensor names in SensorNavigator auto build mode
- More meaningful logging when failing to build sensor trees

- If no sensor hierarchy is specified, SensorNavigator will build a
tree by interpreting each sensor name as a dot-separated path
- Minor changes to README

- MaxMsgNum configuration parameter now defaults to 0 (no message cap)
- The sensor hierarchy string is now logged at startup
- A rebuild of the SensorNavigator is now triggered only at plugin
reloads over the REST API

Make use of mosquitto_max_inflight_messages_set() and the new mosquitto_max_queued_messages_set() functions to limit the amount of memory spent in mosquitto for queued messages.
Rework the handling of disconnects/reconnects

- REST API now correctly performs data analytics computations on
duplicated streaming analyzers
- In duplicated streaming analyzers, the unit that is exposed through
getUnits() is only the one on which that specific analyzer is working.
The units of the other sibling analyzers are still accessible through
the internal _units vector

- When instantiating analyzer units, the sensor tree can be navigated
vertically through the "topdown N" and "bottomup N" keywords, which
respectively mean "N levels down from the top" or "N levels up from the
bottom" of the sensor tree
- This renders the "unit - X" syntax obsolete

Add isTemplate parameter to readSensorBase() and readSensorGroup() to reduce debug output for templates