Validate the JSON columns in Node as a Hash/Array rather than a String
* db/migrate/001_create_base_schema.rb: remove models table

We won't need that.
Remove all traces of an active_model; we don't need that
* spec/spec_helper.rb: conveniences for dealing with model objects
Binding of policy to nodes
Basic functionality for data-driven installers
Associate an installer with a policy by name
* lib/razor/data/node.rb: maintain a log for each node
Node: maintain a boot count, which is reset every time a new policy is bound
Support for interpolating installer templates, including boot templates

This adds routes for fetching templated files directly, and for getting the
next (ipxe) file to boot with
Remove notion of policy templates - these are now installers
Support storing an IPAddress that the node sends us
* db/migrate/002_create_base_schema.rb (nodes.hw_id): change unique constraint

The hw_id must be case-insensitively unique
Razor::Config: remove unneeded class level accessors

The right way to access config settings is Razor.config[key]

Instead of Razor::Config.config, write Razor.config
Instead of Razor::Config[key] write Razor.config[key]