Store user preferences for languages

Also, refactor tests such that we're not deleting users or prefs

lms/envs/common.py

@@ -698,6 +698,10 @@ MIDDLEWARE_CLASSES = (
     # Allows us to dark-launch particular languages
     'dark_lang.middleware.DarkLangMiddleware',
 
+    # Allows us to set user preferences
+    # should be after DarkLangMiddleware
+    'user_api.middleware.UserPreferenceMiddleware',
+
     # Detects user-requested locale from 'accept-language' header in http request
     'django.middleware.locale.LocaleMiddleware',
 

lms/templates/dashboard.html

@@ -83,15 +83,17 @@
              });
     });
 
-    $("#change_language_form").submit(function(event, xhr) {
-      $.post('/i18n/setlang/',
-        {"language": language,},
-        function(data) {
-          if (data.success){
-            location.reload();
-          }
-          })
-      });
+    $("#submit-lang").click(function(event, xhr) {
+        event.preventDefault();
+        $.post('/user_api/setlang/',
+            {"language": $('#settings-language-value').val()})
+        .done(
+            function(data){
+                // submit form as normal
+                $('.settings-language-form').submit();
+            }
+        );
+    });
 
     $("#change_email_form").submit(function(){
       var new_email = $('#new_email_field').val();

lms/templates/dashboard/_dashboard_info_language.html

@@ -1,7 +1,4 @@
 <%! from django.utils.translation import ugettext as _ %>
-<%!
-  from django.core.urlresolvers import reverse
-%>
 
 <%namespace name='static' file='../static_content.html'/>