Support for setting intensity level of Dimmable Switch devices

[signal15]

Add the option to use the Dimming function for the onURL for Dimmable switches so one can set the intensity level.

Looks like you can do this with SwitchPower1, but it appears that not all devices support doing that. Will likely have to use Dimming1.

[bwssytems]

I'm trying to figure out if this is solved with the dimming variables or not. I do not see anything else to set in the vera other than SetLoadLevelTarget which is a percentage.