Voltage in electric part descriptions

[Steffen]

I like this idea. I have 2 thoughts to share:

- please don't use the lowercase "v", but the standard Volts abbreviation uppercase "V"

- many parts already have this in their name: 12V, 4.5V, 9V:
              http://www.ldraw.org/cgi-bin/ptscan.cgi?q=12V
              http://www.ldraw.org/cgi-bin/ptscan.cgi?q=4.5V
              http://www.ldraw.org/cgi-bin/ptscan.cgi?q=9V