Add a "staging" environment

All settings are inherited from the production environment.
Add Unicorn config for the staging environment
Update config files, deploy scripts for the new staging env
We can leave this out, as it is not used no more
Merge pull request #676 from quintel/staging-env

Add a "staging" environment
Renamed co2_free_factor method to co2_factor
Renamed co2_free to free_co2_factor
Renamed part_ets into takes_part_in_ets
Remove energy_import_steam_hot_water from input_defaults.rb
Merge pull request #677 from quintel/heat_import

Remove energy_import_steam_hot_water from input_defaults.rb
Removed entries for chemical industry from bulk update script.
Update bulk_update.rake for renaming industry_useful_demand_useable_heat_efficiencty.
Added user message to bulk_update script.
Updated input defaults.
Merge pull request #678 from quintel/industry

Update bulk_update.rake for renaming industry_useful_demand_useable_heat_efficiencty
Use public (HTTPS) address for deployment
Add Out-of-Band GC

See http://tmm1.net/ruby21-oobgc/
Update GcTools
Update old Rails default error pages

Removed the old files in favour of those from a new Rails project. The
old files expected to be passed through ERB (to insert the rails env).
Pointing to new atlas