SonarCloud on Nemo

[송원욱 <wo...@apache.org>]

Hi all,

For those who are not yet aware of, our Nemo repository has an automatic
travis job set up that runs SonarCloud while building the project for the
periodic master branch build checks. You can get access to the SonarCloud
service through this link
<https://sonarcloud.io/dashboard?id=edu.snu.nemo%3Anemo-project>.

To keep our code clean, please check if the specific branch doesn't produce
additional potential errors detected by SonarCloud, by running the script
under ./bin/sonar_qube.sh before merging a PR. :)

Thanks!
Wonook