- cache ms<->clockcycles conversions
- move callback invocation outside of ISR handler
- remember last event value

- dynamic number and address setting
- do not return i2c-specific error for wrong values

* Add reactive power calculation and bring output to in line with HLW8012 sensor based units

* Update CSE7766Sensor.h

* Fix energy ratio input for pulse meter sensor

* checkout origin/dev -- webui files

* Testing branch

* Added ability (by define) to scale analog sensor, also with number of decimals (it was formerly zero)
Useful when running on batteries to check the battery voltage just 
adding the appropriate resistor

* Reverting DHTSensor.h file

* Trying again to revert DHTSensor.h

* Using macro DEBUG_MSG

* fix method types

* Testing branch

* Added ability (by define) to scale analog sensor, also with number of decimals (it was formerly zero)
Useful when running on batteries to check the battery voltage just 
adding the appropriate resistor

* Reverting DHTSensor.h file

* Trying again to revert DHTSensor.h

* Using macro DEBUG_MSG

* fix method types

* Works with many different ultrasonic sensor models: HC-SR04, SRF05,
  SRF06, DYP-ME007, JSN-SR04T & Parallax PING)))™.
* Built-in digital filter method ping_median() for easy error correction
  (use SONAR_ITERATIONS build flag to configure).
* Allows setting of a maximum distance where pings beyond that distance
  are read as no ping or clear (use SONAR_MAX_DISTANCE build flag).