Merge pull request #2567 from thiagotalma/master

Fixed typos
Enhanced parsing the accept header.
Use default appliaction language in DatePicker

Fix https://github.com/yiisoft/yii2/issues/2562
Update CHANGELOG.md
Change AssetBundle.register() return type to static

Enable IDE typehints for custom AssetBundle properties (related to #2572).
added unit test for #2568
Merge pull request #2574 from andy5/patch-1

Change AssetBundle.register() return type to static
added server name, for creating url rules
Merge pull request #2576 from Ragazzo/yii2_basic_tests_bootstrap_fix

added server name, for creating url rules
Remove language check from DatePicker
Changed `Controller::afterAction()`, `Module::afterAction()` and `ActionFilter::afterAction()` to pass `$result` by value instead of reference
Fixed test break.
Added `Pagination::getLinks()`
fixed a bunch of typos and errors
Merge pull request #2573 from andy5/datepicker-language

Use the current appliaction language in DatePicker
Query::queryScalar wasn't making SELECT DISTINCT queries subqueries
Fix for logic Query::queryScalar uses to check for SELECT DISTINCT
Added support for reading page size from query parameters by `Pagination`
Merge branch 'master' of git://github.com/yiisoft/yii2
Merge pull request #2581 from jom/query-scalar-fix

SELECT DISTINCT queries made subqueries in Query::queryScalar