Remove twentysixteen exception from nightly-builds script

We’d like to bring Twenty Sixteen to trunk, alongside all other default themes.
For that the nightly build script in /usr/local/bin/make-nightly.sh would need to be adjusted not pull in the theme from GitHubGitHub GitHub is a website that offers online implementation of git repositories that can can easily be shared, copied and modified by other developers. Public repositories are free to host, private repositories require a paid subscription. GitHub introduced the concept of the ‘pull request’ where code changes done in branches by contributors can be reviewed and discussed before being merged be the repository owner. https://github.com/ anymore. [dotorg13183] removed that from the releaseRelease A release is the distribution of the final version of an application. A software release may be either public or private and generally constitutes the initial or new generation of a new or upgraded application. A release is preceded by the distribution of alpha and then beta versions of the software. script already.

It would be great if it could be adjusted before the next planned release, RC2 on June 1st. Thank you!

#prio2