Added skeleton and basic deps for EC2 backend
OsTpl and ResourceTpl impl for EC2 backend

* Basic configuration
* Impl. os_tpl from EC2 images (really slow)
* Impl. resource_tpl from fixtures (EC2 API??)
Added caching support to make EC2 usable
Switched default region for EC2 to eu-west-1
Added basic compute parsing/listing for EC2
Added error handling for EC2 backend
Reporting service outages as 503, not 500
Added resource_tpl fixtures for EC2 backend
Added resource_tpl handling when parsing from EC2
Added delete and delete_all for EC2 backend
Updated caching for EC2 os_tpls (only ids, names)
Added basic compute_create for EC2 backend
Added support for resource_tpl in EC2 backend
Added support for user_data in EC2 backend
Adding state information and actions for EC2 VMs
Added links to parsed EC2 instances
Fixed ntwrkintf links for EC2 backend
Fixed parsing of EC2 instances w/o net intfs
Added reservation mixin to EC2 backend
Added support for actions in EC2 backend

Supported:
* start    (on suspended)
* stop     (on active)
* restart  (on active)