Histo command

Make the histo command more of a real thing

```
Usage: histo [options]
 -p <measure> : Parse shades formatted data and histogram a specific measure given as the last argument
 -n <num>     : the max number of bins to include in the output (default = 10)
 -w <width>   : the width of the histogram bars (default = 30)
 -l           : output ascii art on a log scale (default is linear).
              : tip: if the value distribution looks linear using this option then you're dealing with a power law.
 -h           : show this usage
```

Resolves #8 #7 #6