jQuery UI DatePicker widget
InputWidget base class
DatePicker rework
flat => inline
Added missing phpdoc
language as code, not bundle
Merge pull request #378 from creocoder/jui-datepicker

[READY] jQuery UI DatePicker widget
jQuery UI autocomplete widget rework
Merge pull request #409 from creocoder/jui-autocomplete-rework

[READY] jQuery UI autocomplete widget rework
fixed framework path of req checker + notice on wrong path

git ignore composer.lock
added doc comment to Console::getScreensize()
adjusted Exception error page header and title

make sure all information is displayed
Fixes comment by @creocoder issue #408
https://github.com/yiisoft/yii2/pull/408#issuecomment-18454179
Added support for previous exceptions

PHP supports exception stacks since 5.3 so we should use it.
Also Errorhandler is now able to display the stack: #297