Add proxy option to configuration.

This adds a proxy option to the configuration. In the Vagrantfile we can
override this with a specific value and have it passed down to the Fog
API connection options.

The initialization of the Connection object takes a params hash with
the :proxy attribute:
https://github.com/fog/fog/blob/master/lib/fog/core/connection.rb#L22

This is wired up from both the Compute and Network OpenStack instances:
https://github.com/fog/fog/blob/master/lib/fog/openstack/compute.rb#L311
https://github.com/fog/fog/blob/master/lib/fog/openstack/network.rb#L205
Add travis.yml file to the project.
Add a little debugging output.

While testing it is helpful to be able to set VAGRANT_LOG and get debug
output from the settings. This is mainly to verify that proxy is
actually getting down into Fog objects.
Merge pull request #31 from johnbellone/master

Add proxy option to configuration.