Adds support for Travis builds to produce auto-published package files. Each job can create its own package file, using existing support in runsuite*.cmake and package.cmake with some additions here to enable and tweak that code. Longer-term we may want to use package.cmake instead and even make official builds on Travis (i#2861).
Adds Travis deployment to Github Releases of produced packages files. The tag is "cronbuild-${VERSION_NUMBER}": e.g., "cronbuild-7.0.17592".
Adds better support for 32-bit-only or 64-bit-only x86 package files by naming them differently and removing the drrun warnings on incomplete packages when missing the opposite bitwidth.
Issue: #1967 (closed)