Add support for SetUISpilloverCmd

[cryptk]

Message Type is 311, XML body of the command:

<?xml version="1.0" encoding="utf-8"?>
<Request>
  <Name>SetUISpilloverCmd</Name>
  <Parameters>
    <Parameter name="PoolID" dataType="int">1</Parameter>
    <Parameter name="Speed" dataType="int">50</Parameter>
    <Parameter name="IsCountDownTimer" dataType="bool">0</Parameter>
    <Parameter name="StartTimeHours" dataType="int"></Parameter>
    <Parameter name="StartTimeMinutes" dataType="int">0</Parameter>
    <Parameter name="EndTimeHours" dataType="int">0</Parameter>
    <Parameter name="EndTimeMinutes" dataType="int">0</Parameter>
    <Parameter name="DaysActive" dataType="int">0</Parameter>
    <Parameter name="Recurring" dataType="bool">0</Parameter>
  </Parameters>
</Request>

The spillover is associated with the pool that gets spilled into. The speed parameter appears to mirror the speed parameter for the filter pump for that pool.