Change the way user properties are stored in localStorage

Now everything that is associated to a given user will be stored in the
localStorage with a key having the user id as a suffix
Merge branch 'master' of https://github.com/thefuture2092/monlift-client
load user cars and user lifts from server at first login

When logged in for the first time and when no user cars or user lifts
exist in local database, load it from the server
Merge forms.js with Patrice