Also tweaked cmd/cmdPrint to make them more beautiful and functional,
and a few other minor changes, such as using a new idiom for verbose.

These changes support reinstating the examples.

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

PYTHONPATH mods are no longer required for installation.

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

low-level primitives.

The "nox.py" example attempts to use nox as a controller rather than
controller(8).

More edits for INSTALL and README, and refinements for sshd and xterm
examples.