travis-ci: import travis yaml controller

.travis.yml is used for automatic builds on travis build farm
(https://travis-ci.org/) if the travis service hook is enabled for the
repo on github.

This inital yaml controller will run 2 different compilers (gcc, clang).
The test suite currently fails, that's why we don't abort yet.
Merge branch 'master' of https://github.com/rudimeier/util-linux

* 'master' of https://github.com/rudimeier/util-linux:
  travis-ci: import travis yaml controller