Show "title" when using a non-multiple select.

A blank option is prepended to the select, which is then selected by
default. This allows the title to be shown when the select is initially
loaded and "no" options are selected yet. Close snapappointments#888. Close snapappointments#738.

dist/js/bootstrap-select.js

@@ -387,7 +387,8 @@
     createLi: function () {
       var that = this,
           _li = [],
-          optID = 0;
+          optID = 0,
+          titleOption = '<option class="bs-title-option" value="" selected></option>';
 
       // Helper functions
       /**
@@ -423,9 +424,15 @@
             '</a>';
       };
 
+      if (this.options.title && !this.multiple && !this.$element.find('.bs-title-option').length) {
+        this.$element.prepend(titleOption);
+      }
+
       this.$element.find('option').each(function (index) {
         var $this = $(this);
 
+        if ($this.hasClass('bs-title-option')) return;
+
         // Get the class and text for the option
         var optionClass = $this.attr('class') || '',
             inline = $this.attr('style'),