#4 Add logging to the 'settings' object

[Michael P. Reilly]

Release: 1.9b1-src
Fold into: 1.9b2

Add logging inside Expect by allowing to change the
log_file related variables. Three attributes have been
added to the 'settings' object: logfile, logall,
debugfile. See the related patch for the documentation
for more information. The file oriented attributes can
only take None or a file object, it cannot take a
file-like object (e.g. StringIO).

[Michael P. Reilly]

expect.c-diff