Clarified ACL node lookup failed error.

Original error was ambiguous in stating whether the ARO node lookup failed or the ACO node lookup failed.
Don't return `true` from view classes' render() method.

It cause's Controller:render() to set the response body as `true`.

Refs #2780
Merge pull request #2785 from ADmad/2.4-view-return-value

Don't return `true` from view classes' render() method.
Merge pull request #2782 from jimmymadon/feature-clarify-acl-errors

Clarified ACL node lookup failed error.
Minor documentation corrections about Router::connect().
Minor comments only. Added more explanation of $defaults parameter to Router::connect(). Trying to clarify how it relates to the routing destination and the template string tokens.
Merge pull request #2786 from sam-at-github/master

Router::comment() documentation