Small addendum for calc units table (patch included)

[Ulrich Mueller]

For some reason calc's units table misses an entry for the
permittivity of vacuum, while permeability of vacuum is included.
<http://en.wikipedia.org/wiki/Permittivity_of_vacuum>


2008-11-19  Ulrich Mueller  <address@hidden>

        * calc/calc-units.el (math-standard-units): Add eps0,
        permittivity of vacuum.

--- emacs-orig/lisp/calc/calc-units.el  2008-10-08 10:25:42.000000000 +0200
+++ emacs/lisp/calc/calc-units.el       2008-11-19 08:56:02.000000000 +0100
@@ -259,6 +259,7 @@
               "6.62606896 10^-34 J s (*)")
     ( hbar    "h / (2 pi)"                  "Planck's constant" ) ;; Exact
     ( mu0     "4 pi 10^(-7) H/m"            "Permeability of vacuum") ;; Exact
+    ( eps0    "1 / (mu0 c^2)"               "Permittivity of vacuum" )
     ( G       "6.67428*10^(-11) m^3/(kg s^2)"    "Gravitational constant" nil 
               "6.67428 10^-11 m^3/(kg s^2) (*)")
     ( Nav     "6.02214179*10^(23) / mol"    "Avagadro's constant" nil