Weeco4mGPIO first review from feedback

Code changed starting from first feedback from fields:

1. added new parameters on "systemconfig.xml" to set the split point of the digital input used as ON/OFF or Energy Meter S0 Pulse:
      <Interface Domain="EmbeddedSystems.Weeco4mGPIO" IsEnabled="true">
        <Options>
          <Option Name="InputPin" Value="6" />
          <Option Name="PulsePerWatt" Value="1.0" />
        </Options>
      </Interface>
In this moment no needs to add the two parameters on the web guy, but it's an item on the TODO list.

2. changed Weeco4mGPIO class to optimize and reduce the messages which will slow down the web interface and added an watt measure estimator when no pulse S0 arrive (i.e. because the load is fall down and the next pulse will arrive in 30-60sec..)