All commands should work now.

There is probably a better way of doing this, but currently
parseCustomFile can modify globals (e.g. TOPOS) as well as
instance variables (self.validate) and classes (e.g. MyTopo),
which are also in the global name space.

Inconveniently enough, lambdas don't seem to be full closures
in Python; if they were, this trickiness would be unnecessary.

Even so, using execfile() seems like it might be a bit dubious...

This increases flexibility by allowing a topology to be manually created
in Python, or specified using another format, without having to create
a Topo object first.

However, Topos are useful, and are still the default topology object!

Shell now works (although we should use quietRun instead to avoid
file descriptor problem!)

exit/quit/EOF now all exit.

Renamed pingall and pingpair to make them easier to type - I think
commands should not require use of the shift key in general, although
ping-all and ping-pair might be OK.

Simplifies installation step

Defining custom topologies, switch types, controllers, and hosts is now
much easier.  Plus, all Ripcord-specific stuff has been moved out.

Convert CLI to use Python Cmd object, which provides line editing.

with the exception of topo.py, which I haven't touched.

- some namespace conflicts due to unpep8
- fixed infinite recursion caused by removing redundant makeIntfPair

'unpep8' script, which does most of the work.

- topo.py is still in pep8
- not all examples work, but this is due to other issues

does most of the work.)

topo.py is still in pep8, however

We may wish to re-enable this later.

Updated other files accordingly.

It's possible that mn_clean is a bit easier to read; mnclean may be easier
to type, however.

Added variables to Makefile so that source files are listed in a single
location.

The packages argument was incorrectly specified, leading to an install
process that would appear to have succeeded, but would not actually copy
code.

The error likely occurred due to copying setup.py from another project
where the source files were located in a different position relative to
setup.py.

This required a change to logging, which now uses a singleton pattern.

For all future checkins, 'make codecheck' should pass.

Switches and controller in root namespace only, for now.