There were some compiler warnings that crept in recently in the MAMDA area that I didn't notice at code review time because travis / appveyor builds don't currently fail on warning. Instead, the warning is only reported when the PR is merged into next and the Jenkins CI environment picks it up. I've come back and cleaned these up myself as part of these changes.
With this in mind I have made the following changes to the automatic PR code check systems:
1. I have retired travis. Appveyor now supports Ubuntu as well as Windows builds anyway (and more recent versions of Linux than Travis supports so you generally benefit from stricter gcc warnings). This means there's no longer any compelling reason to support both systems so I've turned travis off.
2. I have updated the build system to include -Werror so CI will now fail in the event of a compiler warning being produced.
3. Linux test builds now use cmake rather than scons. Note the next release will have scons removed so please try it out in your local builds.
Note that I would have also modified valgrind to report on compiler warning but ubuntu looks like it currently reports errors that arent present on centos but that's a fight for another day, so I held fire on that one.