Added closeOnSelect attribute
merge from upstream/master
Merge pull request #362 from TravisTX/feat-closeOnSelect

Added closeOnSelect attribute
Make $select.multiple definition more readable.
Support `multiple="multiple"` attribute.

Some html preprocessors will transform

<ui-select multiple></ui-select>

into

<ui-select multiple="multiple"></ui-select>

which is currently not supported by angular-ui-select. This patch fixes the
issue.
Merge pull request #407 from ctavan/allow-multiple-multiple-attribute

Support `multiple="multiple"` attribute.
updating readme to link to docs now that they are all migrated
Add ‘minimumInputLength’ configuration option
Only show results if minimum input length is reached
Only call refresh function if minimum input length is reached
Clear results if input is below minimum input length
Add minimum input notice to Select2 theme
Add minimum input notice to Bootstrap theme
Style minimum input notice in Bootstrap theme the same as other results
Add minimum input notice to Selectize theme
Style minimum input notice in Selectize theme the same as other results
Add tests for minimumInputLength option
Add ‘countChoices’ test helper
Add tests for minimum input feature
Add minimum input tests for every theme