Multiple Module Changes

Sorry if this is a bit messy, I'm new to merging, Github, etc..  I have successfully deployed several times using my changes.  Here is an overview of my changes:

1. Improved dependencies.
2. Flexible external bridge creation.
3. Removed external_ids as not required by OVS and caused a puppet change loop during agent runs.
4. Separated quantum_plugin_ovs related to VLAN mode from base config.

You can find an illustration of the networking model here:  http://docwiki.cisco.com/w/images/f/f3/Network-topology-v1.0.png

As you can see, the model follows the deployment example from the Quantum documentation.