Most of the way to log plots

Hi All, OK, I've got tick/grid positioning and labeling

    > working now, too.

Thanks! I have incorporated your changes into CVS, and added some new
functions to (semilogx, semilogy, loglog). I have done some
additional work to make the tick labels and automatic view lim behave
properly (eg, labeling only the decades, which becomes important for
data with a wide range of decades, and doing a better job of
autosetting the view lim for log scaling). There is still some work
to be done, for example to properly handle the case where the axis lim
are set by the user, and where the scale is changed interactively, but
I thought the existing code was useful enough to do a new release of
the sourceforge site, 0.29.2.

One the remaining issues are cleared up, I want to do a release to the
wider python community, so please report any bugs.

Thanks again, Andrew. Keep them coming.


Some example code :

from matplotlib.matlab import *

dt = 0.01
t = arange(dt, 20.0, dt)

semilogy(t, exp(-t/5.0))

semilogx(t, sin(2*pi*t))

loglog(t, exp(-t/10.0))