added ranger to writelog/readlog

Attached is a patch on the current trunk that adds the ranger interface to writelog and readlog. Because readlog assumes there is a single configuration request for a device but ranger has separate GET_CONFIG and GET_GEOM requests, I had to do a bit of trickery to get this to work, but it does indeed work.

Given that this is supposed to be the new standard interface for range devices, I was sort of surprised (and a bit annoyed) that someone had not already done this.