fixes #1284

Checkboxlist documentation fix

"Item" parameter keys are the values of the checkbox list,
while the values are the checkbox labels.

Fix doc

Renamed DetailView attribute "type" to "format"

for consistency with GridViews DataColumn where the same property is
also named format

avoid XSS with emails in format  "Carsten Brandt <mail@cebe.cc>"

"yii\swiftmailer\Mailer" transport setup has been advanced to support constructor arguments and plugins.

fix rbac select statement

Update Alert.php to display multiple flash messages for the session.

Cleaned up a few comments ... hope its not my OCD again... :-)

Reverted name to ```closeButton``` to be in sync with the bootstrap ```Alert``` widget.

1. Renamed closeButton to closeButtonOptions. 
2. Generate unique id for each alert box.
3. Moved parent init to the top.

Include Schema in new migrations by default

fixes #1261

worked though all the guide files adjusted structure and
added some missing does

Fixes #1222: removed Slider widget from JUI extension since it's not input widget and a wrapper doesn't really add anything

Changed usage of self to static to allow extendibility

fixes #1244

fixes #1246

Each flash variable can be mapped to a bootstrap alert type through a configuration array passed to this widget.

code style section has been added here:
https://github.com/yiisoft/yii2/wiki/Core-framework-code-style#self-vs-static

verification code for properties:
https://gist.github.com/cebe/7566916

Cleaned up redundant code (and a typo missed earlier).