Update README
Fix directory structure for CakePHP 3.x  #71
Fix warnings
Fix status bar for CakePHP 3.x #71
Fix run command action for CakePHP 3.x #71

exit value is not 0 because exit() is used in CakePHP 3.x.
Fix directory structure for CakePHP 3.x  #71

- Add Element and Layout
- Remove APP_PLUGIN condition
- Fix vendor and plugin
Change return type from List to Set for getAllPluginNames
Fix wrong directory name for CakePHP 2.x

- Element -> Elements
- Layout -> Layouts
Refactoring for element code completion
Refactoring for extend code completion
Improvement for CakePhpModule

- Get file for some directories
-  If plugin name is empty string, change it to null
Improvement for HyperlinkProvider

- show tooltip
- support for plugin name