add pexpect to the standard library, standard "install" mechanism.

[funkyj]

Fredrik Lundh wrote:
> any special reason why pexpect cannot ship with a standard distutils
> setup.py file (or even egg support) ?

<googles distutils>

Oh, apparently there is a standard/builtin python distribution
mechanism called 'distutils'.

I guess on the install issue my only suggestion would be for the
pexpect README to say something like:

To install this package on your system run:

      bash$ python setup.py install

I read the pexpect README file but it didn't say the bit above and I
had never heard of distutils.

Thanks Fredrik!
  --jfc