Fixes yiisoft#1310 Improved API docs for CModel::rules and CModel::ge…

…tScenario

framework/base/CModel.php

@@ -61,7 +61,9 @@ abstract public function attributeNames();
 	 *   And a validator class is a class extending {@link CValidator}.</li>
 	 * <li>on: this specifies the scenarios when the validation rule should be performed.
 	 *   Separate different scenarios with commas. If this option is not set, the rule
-	 *   will be applied in any scenario. Please see {@link scenario} for more details about this option.</li>
+	 *   will be applied in any scenario that is not listed in "except". Please see {@link scenario} for more details about this option.</li>
+	 * <li>except: this specifies the scenarios when the validation rule should not be performed.
+	 *   Separate different scenarios with commas. Please see {@link scenario} for more details about this option.</li>
 	 * <li>additional parameters are used to initialize the corresponding validator properties.
 	 *   Please refer to individal validator class API for possible properties.</li>
 	 * </ul>
@@ -508,7 +510,8 @@ public function onUnsafeAttribute($name,$value)
 	 * be massively assigned.
 	 *
 	 * A validation rule will be performed when calling {@link validate()}
-	 * if its 'on' option is not set or contains the current scenario value.
+	 * if its 'except' value does not contain current scenario value while
+	 * 'on' option is not set or contains the current scenario value.
 	 *
 	 * And an attribute can be massively assigned if it is associated with
 	 * a validation rule for the current scenario. Note that an exception is