Multilanguage module uses mootools modal

#### Move modals from mootools to Bootstrap
FINAL PR to get all back end using bootstrap modals. The rest are: #4513 #4514 #4561 #4562 and #4563  

Testing:
**You need a multilingual site**
After Applying this patch 

Try the button on the sticky bar at the footer (first icon from left to right)

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![screenshot 2014-10-12 11 13 44](https://cloud.githubusercontent.com/assets/3889375/4605526/bdd1c9be-51e7-11e4-9857-70acbeaa7e2e.png)
![screenshot 2014-10-12 11 09 44](https://cloud.githubusercontent.com/assets/3889375/4605527/c1967004-51e7-11e4-8728-a18093d0a419.png)