Add readline to the dependencies for Mac OSX

Some platforms i.e., Mac OSX don't support readline module in the
standard library. This patch adds the explicit dependency declaration to
setup.py to install readline module on the installation.

Signed-off-by: Taku Fukushima <tfukushima@midokura.com>
Add L4LB resources to midonetclient

This patch adds resources specified in our L4LB specification to
midonetclient.

Signed-off-by: Taku Fukushima <tfukushima@midokura.com>
Add L4LB resources to MidonetApi and Application.

This patch adds the connections between the application and the L4LB
resources added by the previous patch.

Signed-off-by: Taku Fukushima <tfukushima@midokura.com>
Add the support of the L4LB feature to midonet-cli

This patch adds the commands for the L4LB featrue to midonet-cli.

Squashed tfukushima/python-midonetclient#1 submitted by @dcahill and
following patches.

Signed-off-by: Taku Fukushima <tfukushima@midokura.com>
Signed-off-by: Dave Cahill <dcahill@midokura.com>
Add doc/*.html to .gitignore

Signed-off-by: Taku Fukushima <tfukushima@midokura.com>
Change help texts of commands to docstrings.

Signed-off-by: Taku Fukushima <tfukushima@midokura.com>
Refactor midonet-cli to use the new style classes

`super()` is only supported in Python3 and I just put the class name and
`self` as an instance for the arguments of `__init__`. It's not
abstracted well but the follwing idiom doesn't work for the classes
which have further derived class because `self.__class__` would be
always the class of the instance `self` and cause the stack overflow.

    def __init__(self, obj):
        super(self.__class__, self).__init__(obj)

See the following links for the further information:

  * http://stackoverflow.com/questions/54867/
  * http://stackoverflow.com/questions/576169/
  * http://www.artima.com/weblogs/viewpost.jsp?thread=236275

Signed-off-by: Taku Fukushima <tfukushima@midokura.com>