Priority queue

This is a bullet list of priority tasks. Definition to come when I have some time to add. Thanks.

• Update docs for helpers
• Update docs for backstop approve --filter
• backstop approve --filter feature
• add local install/running (via bin dir) to docs including file loading, customs file loading and config passing
• remove lagacyMode feature
• add local & global run test to travis script
• properly escape quotes on all config props
• add helper for allAssetsLoaded
• fix rules for overriding/extending engineFlags
• CSS tricks article
• dwb article