Simplify apidoc  to allow for custom renderers via ext
PHPDocs: "app\models" changed to "common\models"
Merge pull request #2095 from kumorig/patch-4

PHPDocs: "app\models" changed to "common\models"
doc typos

fixes #2094
Merge pull request #2086 from jom/apidoc_extendable

Simplify apidoc's RenderController::findRenderer to allow for custom renderers via ext
improved erorr handling in api doc controller
AssetController config template adjusted.