Improved action filter and action execution flow by supporting installing action filters at controller, module and application levels

fix doc code according to yii2 core code style (When instantiating class it should be new MyClass(); instead of new MyClass;.)

Fixes #1577

worked though all the guide files adjusted structure and
added some missing does

Control statements based on the if and elseif constructs must have a single space before the opening parenthesis of the conditional and a single space after the closing parenthesis.