helper.content_render: Move before/after calls to an other class.
Fix #165: Clean up at_ui module.
Fix call undefined method, reported by scrutinizer-ci.com. Thank you again!
Fix #166: New devtool: /at/sql

Provide /at/sql where developer can run SQL directly there.
New in at_ui module: developmenet indicator.
Merge branch 'dev-master' into site/crom

* dev-master:
  New in at_ui module: developmenet indicator.
  Fix #166: New devtool: /at/sql
  Fix call undefined method, reported by scrutinizer-ci.com. Thank you again!
  Fix #165: Clean up at_ui module.
  helper.content_render: Move before/after calls to an other class.