tweaked Z-Wave Device power updates

* The callback no longer checks against the current level to see if the power has changed.  This caused issues where Roomie didn't see one change (when it was not running, for example) and then when the device changed back to where Roomie remembered, no event was triggered.
* Set IsConnected=true in the callback.  This just makes sense
* Removed redundant "this" qualifiers all around.  Huzzah!
yikes, it was all backwards.