refactored apidoc extensions completely.

separated guide and apidoc, better maintainability
Merge branch 'master' into apidoc-refactoring

* master: (153 commits)
  rest doc.
  CS fix
  Add size attribute to Modal
  major features and documentation finished for REST API.
  rest WIP
  Removed U+FEFF character from pt-PT language file to fixe #2631
  Revert "Used ternary operator instead of "or" for constant definition"
  `User` here
  REST wip.
  Changelog
  reset access cache when user identity is set
  Keyboard shortcut for previous, next and refresh buttons
  reset batch query result when rewinding.
  fixed loading namespaceless controller classes.
  Fixes #1467: Added support for organizing controllers in subdirectories
  replace pjax with external resouce via composer
  fixed > 100 typos introduced by me :-)
  fixed condition for HHVM test
  fixed phpdoc
  updated phpdoc references of BaseAR to the interface
  ...

Conflicts:
	extensions/apidoc/templates/BaseRenderer.php
	extensions/apidoc/templates/html/views/constSummary.php
	extensions/apidoc/templates/html/views/propertyDetails.php
improved HelpController with messages for each command
finished guide command refactoring
final changes for apidoc refactoring
Merge pull request #2656 from yiisoft/apidoc-refactoring

Apidoc refactoring