Fix for wrong url after login and issue filters from project overview and issue summary

As described in the title the additions should fix the problem of "double" url after login when accessing a sub page like yourhost/candycane/issues/13. This is further described in the change to AppController.php.

Also fixed should be a problem where filtering issues from the project overview or issue summary didn't work, see also the attached images:
![issue1](https://f.cloud.github.com/assets/1861585/1178346/3086372a-21aa-11e3-8448-ea432f6e62b1.jpg)
![issue2](https://f.cloud.github.com/assets/1861585/1178347/307a424e-21aa-11e3-9b24-f0b6841b19d2.jpg)

Best Regards

Timo / Zhyraxx