Honor the MaxDimLevel property of accessories.
Honor the MaxDimLevel property of accessories.

LightwaveRF lights could not be dimmed properly as they require a dim level
of betwene 0-32. The Domoticz documentation incorrectly states this should be
0-16.

Other devices may use different values which is why the MaxDimLevel property
should be used rather than hardcoded value.

Also refactored the code slightly.

SphtKr/homebridge-zway