Add support for the Motorola DS8611

[jamesmulcahy]

No description provided.

[jamesmulcahy]

My Motorola DS8611 returns whitespace in one of the cells for the upstream channel information. I opted to do leading/trailing space trimming on all cells, since that seemed like it'd be more durable. It's probably fair to say that if one cell can get some leading whitespace, the others can too (if the values are low enough, perhaps).

I added a test including the exact output from my device -- and the existing tests continue to pass.

Let me know if you'd like any changes, @jahkeup