#95 Cannot use prefix as variables

[Ton van Overbeek]

From an email by jtuttle at gmail.com:
You can't use any metric prefix as a variable without
parenthesis
(for example, the expression "x = 1" gives an error).
Not sure if this
is a problem, but a preference to turn off the prefixes
and/or let you
use them as variables would be helpful.