A few corrections to the matplotlib user's guide

Hello,

I've read the user's guide this week (which is great, by the way), and
wrote the small mistakes I've encountered. Here are my suggestions:

p. 27: thus you can call *any* Axes...
p. 28: the axes command *is* initialized...
p. 36: "Often times" doesn't sound correct to me.
p. 37: *the* color mapper transforms
p. 43: "click)" (no "}.")
p. 49: should there be also "yminorLocator"?
p. 52: "points are specified using a python's datetime module" -> "by
using python's datetime module"
p. 63: "you can create any plots using pure OO code that you could
create with the pylab interface" -> "you can create, using pure OO
code, any plot that you could create with the pylab interface"
p. 63: info 3 parts: the *pylab* interface (perhaps also change 3 into
"three", if I think about it)
p. 63: "calls to the backend renderer" -> "calls the backend renderer"
p. 63: which in turn *knows* nothing about
p. 64: it is potentially useful *for* developers
p. 66: which *uses* the rc information
p. 66: "verbose.erro" -> "verbose.error" (I presume)
p. 67: if an exception is *raised*
p. 71: put a period after "configuration file"
p. 71: *that* is, where matplotlib installs *its* data files.

I hope this helps,
Noam