Renames AccessDeniedHttpException to ForbiddenHttpException as in #2103
Deletes AccessDeniedHttpException
Adds UnauthorizedHttpException class for 401 errors
Adds GoneHttpException for 410 http errors
Adds NotAcceptableHttpException for 406 Http errors
Adds ConflictHttpException for 409 http errors
Adds TooManyRequestsHttpException for 429 http errors
Adds UnsupportedMediaTypeHttpException for 415 Http errors
Renames AccessDeniedHttpException to ForbiddenHttpException in framework, docs, and extension files
Merge pull request #2114 from thiagotalma/master

Adjustment the translation into Portuguese of Brazil.
Fixes #1974.
Added `beforeRun()` and `afterRun()` to `yii\base\Action`
Fixes #2079:

- i18n now falls back to `en` from `en-US` if message translation isn't found
- View now falls back to `en` from `en-US` if file not found
- Default `sourceLanguage` and `language` are now `en`
Adds docblock comments and HTTP spec links for the new HTTP Exception classes (#2103)
Merge branch 'master' of git://github.com/yiisoft/yii2 into 2103-rename-accessdeniedhttpexception
Removes Map file uploaded accidentally
Condenses changelog notes to 1 line (#2103)
Removed temp class
Merge pull request #2106 from danschmidt5189/2103-rename-accessdeniedhttpexception

#2103 improves http exception consistency and adds new subclasses
changelog fix.