Added back dropdownAutoWidth option

This adds back the `dropdownAutoWidth` option, so the dropdown can
have a width that is automatically determined by the browser. This
works best for smaller dropdowns that contain options with large
amounts of text.

This closes select2#3103.
This closes select2#3113.

Signed-off-by: Kevin Brown <kevin@kevin-brown.com>

Author: menthol

dist/js/i18n/ru.js

@@ -4098,9 +4098,16 @@ S2.define('select2/dropdown/attachBody',[
   AttachBody.prototype._resizeDropdown = function () {
     this.$dropdownContainer.width();
 
-    this.$dropdown.css({
+    var css = {
       width: this.$container.outerWidth(false) + 'px'
-    });
+    };
+
+    if (this.options.get('dropdownAutoWidth')) {
+      css.minWidth = css.width;
+      css.width = 'auto';
+    }
+
+    this.$dropdown.css(css);
   };
 
   AttachBody.prototype._showDropdown = function (decorated) {
@@ -4619,6 +4626,7 @@ S2.define('select2/defaults',[
       amdLanguageBase: './i18n/',
       closeOnSelect: true,
       debug: false,
+      dropdownAutoWidth: false,
       escapeMarkup: Utils.escapeMarkup,
       language: EnglishTranslation,
       matcher: matcher,

dist/js/select2.full.js

@@ -4098,9 +4098,16 @@ S2.define('select2/dropdown/attachBody',[
   AttachBody.prototype._resizeDropdown = function () {
     this.$dropdownContainer.width();
 
-    this.$dropdown.css({
+    var css = {
       width: this.$container.outerWidth(false) + 'px'
-    });
+    };
+
+    if (this.options.get('dropdownAutoWidth')) {
+      css.minWidth = css.width;
+      css.width = 'auto';
+    }
+
+    this.$dropdown.css(css);
   };
 
   AttachBody.prototype._showDropdown = function (decorated) {
@@ -4619,6 +4626,7 @@ S2.define('select2/defaults',[
       amdLanguageBase: './i18n/',
       closeOnSelect: true,
       debug: false,
+      dropdownAutoWidth: false,
       escapeMarkup: Utils.escapeMarkup,
       language: EnglishTranslation,
       matcher: matcher,

dist/js/select2.full.min.js

@@ -356,6 +356,7 @@ define([
       amdLanguageBase: './i18n/',
       closeOnSelect: true,
       debug: false,
+      dropdownAutoWidth: false,
       escapeMarkup: Utils.escapeMarkup,
       language: EnglishTranslation,
       matcher: matcher,

dist/js/select2.js

@@ -179,9 +179,16 @@ define([
   AttachBody.prototype._resizeDropdown = function () {
     this.$dropdownContainer.width();
 
-    this.$dropdown.css({
+    var css = {
       width: this.$container.outerWidth(false) + 'px'
-    });
+    };
+
+    if (this.options.get('dropdownAutoWidth')) {
+      css.minWidth = css.width;
+      css.width = 'auto';
+    }
+
+    this.$dropdown.css(css);
   };
 
   AttachBody.prototype._showDropdown = function (decorated) {