New layout and bug fixed

[Added] style.css -> personal empty css file
[Added] bootstrap.js -> to load js functionnality of bootstrap
[Added] bootstrap.ctp -> new layout more bootstrap style
[Removed] default.ctp -> not necessary anymore
[Updated] AppController -> to give a title, description and layout by
default
[Updated] BsHelper -> change the path of jquery, bootstrap js and
bootstrap css
[Fixed] Bug multiple checkbox to save datas' request