TW-11: Uses bootstrap and less
TW-11: renders pictures as tiles with no margin

* uses a bootstrap grid
* uses a navbar
.gitignore: ignores tern files
TW-11: Adds a timestamp to each tile
TW-11: Settings button
TW-11: User link & navbar styles
TW-11: Removes old photos
TW-11: Set a gray as background
Merge branch 'feature/teamwall-11_wall_page' into develop