Si units

Yeah, I know, I am pedantic/obsessive-compulsive about units :)

Anyway, this patch:
- Corrects b to B for bytes
- Corrects K to k for kilo
- Adds a space between the value and the unit
- Uses decimal scale, instead of "informatics" (power of 2) scale

The use of the decimal scale is IMHO better suited for humans. Anyway I'm open for debate over this :)