Linux Buildbot

Use Travis CI.

Notes:
- Need to research the various Linux app bundle projects out there to find out which is good for our needs.
- Might need to statically link Qt? Or all dependencies?
- Should we maintain packages for n distros/versions and m build channels? Ex. Ubuntu 16.04 Release, Fedora 25 Development, Arch Testing?
   - If so, are pre-built packages necessary?