Abridged cpu monitor -- ouputs only usr for each core

I pieced together a plugin which prints only the usr column for each cpu, motivated by [issue #53](https://github.com/dagwieers/dstat/issues/53). This is useful to those who have >10 cores to monitor + memory during remotely executed parallel processing jobs, given that the use of the option **-C 0,1,2,3,...** shows too wide of an output for one's average window size. The plugin is primarily based off code already in *dstat*.