* Use docker to locally run tests on multiple perl versions
* perlbrew used to install multiple perls
* perl environments bootstrapped when image built
* Based on travis configuration
* Adds docker folder to MANIFEST.SKIP
* Running image runs all tests.
* If exit with no error, then all tests pass.
* ./build-docker.sh builds stow testing image.
* ./test-docker.sh runs stow testing image.
* Assumes built with options in build-docker.sh
* *-docker.sh scripts added to MANIFEST.SKIP
http://article.gmane.org/gmane.comp.sysutils.automake.general/13192
This means that it is still included in the distribution and
installed, but is only automatically (re)built when making a
new distribution - if stow.texi changes during development, it
has to be rebuilt manually via 'make pdf'.