"Using 3rd-Party Libraries" guide added
"Using 3rd-Party Libraries" guide updated
Missing "md" extension added for "Using 3rd-Party Libraries" guide part
Merge branch 'master' of github.com:yiisoft/yii2 into 1837-3rd-party-doc
Simplify apidoc  to allow for custom renderers via ext
Fix for #2087
Merge pull request #2090 from lucianobaraglia/2087-pgsql-schema-quoted-indexes

Fix for #2087
Fixes #2091: `QueryBuilder::buildInCondition()` fails to handle array not starting with index 0
PHPDocs: "app\models" changed to "common\models"

Just a minor PHPDocs change. In the advanced application there is no such thing as "app\models".
Merge pull request #2092 from kumorig/patch-2

PHPDocs: "app\models" changed to "common\models"
Added doc.
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.
AssetController default 'cssCompressor' value changed to enforce type css.
Issues #1265 #2084 added to CHANGELOG
Fix typo