Fix user messages

I fixed the local storage service, user messages were jsut working fine.
I updated the UXD, they are now sticky to the right-bottom corner.
Adding overflow markers for preview frame scroller
New scroll overflow design (smaller teeths)
Fix scroller overflows apparitions
Fix background visual design
Update scroller overflows VD + fix zindex bug
Merge pull request #106 from juliandescottes/fix-user-messages

UI Stuff again