some css fixes
fixes #67 Hide unlinked buttons
fixes #66 : Resizing window breaks zoomed camera ratio
remove unlinked buttons from tutorial mode
really center zoomed cam (not with a fake -66% margin-left)
center cameras on window resize
Merge pull request #1 from Paulloz/roomscss

Rooms CSS
[database] move database code in common/
[sessions] can configure session store in configuration file
[sessions] use configured session store to store express' sessions
add sessions storing dependencies and repository to package.json
[database] fix redis' get on undefined id
[database] fix some ID problems with databases
[sessions] rename session storage collection
change chat input into textarea
fix textchat css
fix css for textchat links
update thumbnails display on multiple columns
Merge pull request #2 from Paulloz/roomscss

Some CSS improvements
Merge pull request #71 from azziel149/roomfix

Conflicts:
	src/frontend/modules/camera.coffee
	www/public/css/room.css