Renamed _gas into _network_gas for three converters in buildings sector.
Merge pull request #718 from quintel/renaming_gas

Renamed _gas into _network_gas for three converters in buildings sector.
Update Atlas to quintel/atlas@725a6c7

Removes dependency on an old version of "backports" which doesn't work
with Ruby 2.1.3.
Fix debug formatting for string query results

Closes #720
Revamp *_TABLE debug formatting

Adds an HTML table with anchored headers, as well as CSV, TSV, and text
copies. Clicking on the CSV, TSV, or text will select it to make for
easy copying.

Ref #720
Tweak a table header background
Style tweaks to the GQL test page
Style the GQL debug form
Improve styling of the navbar

* Local / Beta / Staging now shown next to the application title in an
  appropriate colour.

* Decluttered the navigation by moving items to subnavs.
Further *_TABLE display improvements

* Link to converter when displaying the key.
* Make the columns sortable.
* Better formating of numeric values.
Fix "sorted" table header backgrounds