IVSSwitch: add an option to control the --verbose flag

support batch shutdown for IVS

Each switch class will be called to shutdown its own instances.

Not a single command like the OVS one, but it still greatly decreases the
shutdown time.

This does assume that stop() is called after batchShutdown(), which is true in
the current mininet code.

Add a timeout parameter to the pingAll command

OVS switch connect to controllers using protocols other than TCP like SSL.

    net.addController( 'c0', protocol='ssl' )

This now allows OVS to connect to a controller using SSL.  The default of protocol is 'tcp'
as it currently is.

Enable batch startup/shutdown of OVS

Not perfect, but it moves us forward at least.

Netstat: do not resolve addresses

Ping: packet loss should be a float

 Uploading MiniEdit 2.1.0.7.1

    OVS install Ubuntu packages

IVSSwitch: wait for ivs to terminate before tearing down node

persistent command history

This was a problem when running IVS in a container. IVS would begin the process
of closing controller connections on receiving SIGTERM, but often mininet would
have continued on and removed the control network interface from the container
before it could send the FIN. The controller wouldn't know the connection had
been closed until it timed out much later.

Saves readline history to ~/.mininet_history.

(pending) mnexec: mount sysfs in each container

checking with non-numeric characters.

    This argument expect a parameter which is the version number of OVS you wish to install.
    install.sh -V 2.0.0

    What is nice that I tested, is that you can keep running the above to change
    which OVS version you want to test with.  Also, if a new version of OVS
    is released, just run the above again specifying the new version number.

    The version number must match the version number in the tarball file name
    like openvswitch-2.0.0.tar.gz.  In this case, the version specified
    must be 2.0.0.

fixes #279

This saves about 10 seconds for a 200 switch network.

This seems slightly ugly, but it has bitten many people.

Closes #268