marker color handling: matplotlibrc versus args and kwargs

On another note, I get messages like

  mpl/examples> python simple_plot.py -dAgg
  Bad key "lines.markeredgecolor" on line 48 in
  /home/jdhunter/.matplotlib/matplotlibrc.
  You probably need to get an updated matplotlibrc file from
  http://matplotlib.sf.net/matplotlibrc or from the matplotlib source
  distribution
  Bad key "lines.markerfacecolor" on line 47 in
  /home/jdhunter/.matplotlib/matplotlibrc.
  You probably need to get an updated matplotlibrc file from
  http://matplotlib.sf.net/matplotlibrc or from the matplotlib source
  distribution

since I did yet not update to the new rc which is to be expected. I
know from experience that neophyte users are confused by this. Many
mpl users don't even know that an rc file exists, what it is for, and
how to find it. While you are mucking around in rc and __init__.py,
you might consider a more helpful deprecation message scheme, with
part of the message boilerplate and part of the message specific to
the bad rc key. Eg, if a user has lines.markerfacecolor in his rc:

  The setting "lines.markerfacecolor" in your parameter file
  /home/jdhunter/.matplotlib/matplotlibrc is deprecated in this
  version of matplotlib. The configuration for marker facecolors was
  your was recently changed. blah blah blah explain the new interface
  and behavior. You may want to replace
  /home/jdhunter/.matplotlib/matplotlibrc with the latest file
  http://matplotlib.sf.net/matplotlibrc .

Something to think about.

JDH