[#41] Questions to save delivered as a JSON request to smileplug

This pull request is linked to the following issues : 
On 'smile_teacher_android' side: https://github.com/SMILEConsortium/smile_teacher_android/issues/41 
On 'node_smile_server' side: https://github.com/SMILEConsortium/node-smile-server/issues/26

Now, the teacher app send a JSON request with "title" and "iqdata"
This change also fix a layout bug on Nexus 7 for "Use prepared questions"