Restored menus : sessions list, speakers, members, staff.
Sessions list : port submission alert block to bootstrap 3.
New page+menu : code of conduct
Footer: Code of conduct link instead of "Copyright Mix-IT 2014". Fixes mix-it/linkit#178
Code of conduct page: two columns layout.
Code of conduct page: icon outside link
Code of conduct; fixed English typos.
Merge pull request #181 from clacote/feat/178-code-of-conduct

Code of conduct
Merge pull request #180 from clacote/public-sessions-list

Public sessions list