deb package built by travis does not work wit ubuntu 18.04

[jnweiger]

Travis runs Ubuntu 16.04 - the imagemagick version there is incompatible with Ubuntu-18.04

• we could build a autotrace-mini package --without-magick, that should work on all Debian and Ubuntu systems.
• we could convert .travis-ci.yml to matrix syntax and firing up docker containers. That should also help to disentangle the current linux || osx hacks.
• static linking is not possible as libpstoedit.a is missing in ubuntu-18.04's libpstoedit-dev package.

Workaround: https://github.com/jnweiger/autotrace/releases has an autotrace_0.40.0-20180903-ubuntu1804_all.deb package.

[lemenkov]

We should switch to Docker builds. it allows us to build against anything which is available at Docker Hub.

[nicolas-raoul]

@jnweiger About your workaround: I don't see any *ubuntu1804_all.deb file at https://github.com/jnweiger/autotrace/releases , would you mind explaining how to find it? Thanks!

[jnweiger]

@nicolas-raoul Hmm, its gone missing. Re-added:
https://github.com/jnweiger/autotrace/releases/tag/0.40.0-20190312

@lemenkov I am afraid I have to hunt for the solution with the least effort on my part. Docker builds are definitly possible, but much more effort to maintain.

@probonopd Maybe we should roll an appimage here, to have a one-binary-fits-all solution?