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.

Sort interface names before passing to dpctl for kernel switch, so that
links for multipath topologies can be added in any order.

Also use indexing for DPIDs to avoid zeroed MAC

Auto MAC setup sets each host MAC equal to its DPID, which simplifies
debugging.

Auto ARP setup removes the need for broadcast support for ARP, which
enables a smaller NOX controller.

Also simplify test running.

Also remove usused imports and outdated doc text.

Also remove all non-object-oriented legacy Mininet code and update
tests.

User-space compatibility is untested, but most of the code for it is
still in.

Nodes include Switch, Host, and Controller; move these to a separate
file.

This file still could use some attention to hide private functions.
Node seems like a primary class to extend, for adding stuff like Open
vSwitch, so it could benefit from a simpler interface.

Having a file with the same name as its package creates hard-to-diagnose
import error, so rename mininet.py to net.py.  This commit moves utility
functions, generally those dealing with network namespaces and interface
management, into their own file.

Also fix a few minor formatting bugs and clean up logging code (which
had issues when multiple files would import mininet.logging_mod).

Use customized StreamHandler from Python logging module to print
only messages for the specified loglevel to the console.

Don't print retry errors by default.

Was causing OSErrors because the process to kill no longer existed.

Much faster now; from 1 s delay to 100 us.

Now, to reference mininet files, use 'import mininet.mininet'.

PYTHONPATH mods are no longer required for installation.

Useful for monitoring the output of a set of nodes.

- invoke ofdatapath with --fail=closed (no controller = no connectivity!)
- stop hosts before switches before the controller
	- this seems slightly more sensible
	- it's the reverse of the startup order
- fix retry() so it kind of works (it's actually helpful I think!)

Added retry() function for createLink to see if it helps (probably won't.)
Random edits to docs.

Added commentary on control network to mininet.py.
Hopefully fixed linearbandwidth.py for real.