Split existing tests up, and add tests for Router based image URL's

Refs #2233
Fix missing HTML encoding on URL's generated by Html->meta().

The input URL was not correctly handled as an asset URL and thus was
not correctly HTML or URL escaped. This created invalid HTML when
favicon URLs included query string arguments.

Refs #2233
Model.php PHPDoc Description: Chang afterFilter with afterFind
Merge pull request #2300 from cusspvz/patch-1

Model.php PHPDoc Description: Change afterFilter with afterFind
Merge branch 'master' into 2.5