Merge PR #2066 branch '2043-add-support-for-custom-request-parsers' of https://github.com/danschmidt5189/yii2

* '2043-add-support-for-custom-request-parsers' of https://github.com/danschmidt5189/yii2:
  Fixed type in JsonParser
  Tabs vs. spaces
  Added support for custom web\Request parsers (#2043)
  Adds customizable parsing functionality to the web\Request class (Issue #2043)