Refactored Sort.
Added SortTest
Added LinkSorter.
added support for HTTP verb PATCH

To provider better REST API support PATCH method is added which is used
for partial updates, while a PUT should only update whole record.

issues #303 and yiisoft/yii#2664
Directory structure updated in README.md
Removed ListPager and refactored LinkPager and LinkSorter.
Merge pull request #644 from maximal/patch-1

Directory structure updated in README.md
Fixes issue #643
Typo fix [skip ci]
Merge pull request #645 from lucianobaraglia/master

Typo fix [skip ci]
fixed basic app code style
added some phpdoc to advanced app
removed unused line from smarty plugin
fixed code style
added missing return tags to CaptchaAction
added Panel phpdoc
short phpdoc descriptions for Panel subclasses
added missing GettextMessageSource phpdoc
class import cleanup
Refactored Sort.