PR - add an option to dynamically pass in the location of the array

[juggledad]

It would nice if you could pass in the location of the array in the incoming msg.

For instance say I have two arrays of songs - one is for lullaby's (msg.lullabys) and the other is dance songs (msg.dance). I want to grab a song from one array or the other based on the time of the day. I'd like to pass in msg.arrayname which could be 'msg.lullabys' or 'msg.dance'.