[FIX] Special oauth_ methods: force_login param

Fix #81.
We need a `&` sign to append to the existing `url`, which already
contains a `?`.

Author: mynetx

CHANGELOG

@@ -4,6 +4,7 @@ codebird-js - changelog
 2.6.0 (not yet released)
 + Allow to get the supported API methods as array
 - #79 Use POST for users/lookup and statuses/lookup, params may get too long for GET
+- #81 Special oauth_ methods: Fix force_login parameter
 
 2.5.0 (2014-06-23)
 + #24 Add README section about xAuth

codebird.js

@@ -587,7 +587,7 @@ var Codebird = function () {
         }
         var url = _endpoint_oauth + "oauth/authenticate?oauth_token=" + _url(_oauth_token);
         if (params.force_login === true) {
-            url += "?force_login=1";
+            url += "&force_login=1";
             if (params.screen_name !== null) {
                 url += "&screen_name=" + params.screen_name;
             }
@@ -613,7 +613,7 @@ var Codebird = function () {
         }
         var url = _endpoint_oauth + "oauth/authorize?oauth_token=" + _url(_oauth_token);
         if (params.force_login === true) {
-            url += "?force_login=1";
+            url += "&force_login=1";
             if (params.screen_name !== null) {
                 url += "&screen_name=" + params.screen_name;
             }