A bugfix release with a focus on security.

Most of these have been brought to our attention by the community and we are very thankful for that. Special thanks to Michael H., Julian and Michael O., who helped by reporting and assisting us in fixing security bugs. CVEs have also been requested for these issues, they are as follows: CVE-2017-16933, CVE-2018-6532, CVE-2018-6533, CVE-2018-6534, CVE-2018-6535, CVE-2018-6536.