Merge pull request #9 from bigteddy97/master

Implemented online users
Fixed online users count.

Added basic counting of users in threads - not quite working yet.
Added nice online users count text.
Added thread-specific user count.

Limited messages delivered by the server to 200.
Merge pull request #10 from bigteddy97/master

Added Travis-CI build script
Added travis image to readme
Merge pull request #11 from bigteddy97/master

Removed unnecessary NodeJS version from build
Tweaked client online-intervall
Updated travis-ci status image.

Added Placehold.it image to project.
Minor tweaks

Added titles to the threads. Fixed icon not being shown. Altered texts
and made header image round.
Message Sounds

Plays Notification sounds, hopefully works, not 100% sure with bugs