create stack if it does not exist
Added GET /v1/data_centers/template to return the overcloud HEAT template

This is just for the template debugging.
Initial change to compute Heat template to create flavors with UserData script
Added check to Heat script if instance_type does not already exists
Merge pull request #71 from mfojtik/templates

Initial change of the 'compute' Heat template to support creating flavors in Nova
Fixed displaying 'unit' attribute for Rack capacities

NOTE: You **need** to re-run the the sample_data.py script.
Merge pull request #67 from mtaylor/create_stack

Create stack
Fixed tests to support 'unit' attribute for Rack capacity
Merge pull request #74 from mfojtik/capacity_unit

Fixed displaying 'unit' attribute for Rack capacities
Improved handling of Rack state

- Set to 'provisioning' when Heat stack is CREATE_IN_PROGRESS
  or UPDATE_IN_PROGRESS

- Set to 'active' when Heat stack is UPDATE_COMPLETE or CREATE_COMPLETE

- Set to 'error' when Heat stack is UPDATE_FAILED or CREATE_FAILED
Merge pull request #70 from mfojtik/rack_state

Improved handling of Rack state
Fix resource_class links in Rack listings

Fixes https://github.com/tuskar/tuskar/issues/55