Roll Out Framework with Cluster-Formation

These edits move PandaCluster beyond simply creating a CoreOS cluster.  The goal is to setup a deployment environment with a single command.  
### Now you can create a cluster with:
1. Arbitrary public SSH keys loaded on every machine.
2. SkyDNS deployed on every machine.  (This pulls the image, but needs some tweeks)
3. A hook-server deployed.  (This pulls the image, but the service still fails utterly)  

###  Changes
- Build-Template command has been removed
- `public_keys` and `hook_server` fields are now located in the PandaCluster dotfile to configure the cluster.
- The units directory has been moved into src/services.  SkyDNS and the hook-server service files have been added to the library
- Services are launched during cluster-formation by selecting from among those listed in the `units.cson` manifest, much like how arguments are specified.

### ToDos
- I need to work the bugs out of SkyDNS and hook-server services in the cluster.  SkyDNS appears to basically work, but there is something wrong with the hook-server still.
- I need to work out a graceful way to edit the *.service files.  I want to turn them into templates we can manipulate with CoffeeScript.  This should make them much more dynamic that systemd is by intself, haha.
- There needs to be a function to allow the user to select a URL for their cluster.
- None of this is documented yet, so I'll need to do that before I get hit by a truck.  :truck: