bar() and barh() ignore rcparams patch.facecolor and patch.endcolor

Don't know if this is the best way, but here's a solution:

    > def bar(self, left, height, width=0.8, bottom=0,
    > color=matplotlib.rcParams['patch.facecolor'], yerr=None,
    > xerr=None, ecolor=matplotlib.rcParams['patch.edgecolor'],
    > capsize=3 ):

Hey Martin,

We don't put the rc defaults in the function declaration because these
are evaluated only once, at module load time, which prevents users
from being able to change the defaults after the module is loaded. So
we use this idiom

def somefunc(edgecolor=None):
   if edgecolor is None: edgecolor = rcParams['patch.edgecolor']

If you'd like to submit a patch for bar and barh, that'd be great.