ci: introduce Travis builds for GitHub repositories

ci: introduce Travis builds for GitHub repositories

GitHub is a service used by developers to store repositories.  GitHub
provides service integrations that allow 3rd party services to access
developer repositories and perform actions.  One of these services is
Travis-CI, a simple continuous integration platform.

This series introduces the ability for any github mirrors of the DPDK
project, including developer mirrors, to kick off builds under the
travis CI infrastructure.  For now, this just means compilation - no
other kinds of automated run exists yet.  In the future, this can be
expanded to execute and report results for any test-suites that might
exist.

This is a simple initial implementation of a travis build for the DPDK
project.  It doesn't require any changes from individual developers to
enable, but will allow those developers who opt-in to GitHub and the
travis service to get automatic builds for every push they make.

The files added under .ci/ exist so that in the future, other CI
support platforms (such as cirrus, appveyor, etc.) could have a common
place to put their requisite scripts without polluting the main tree.

Signed-off-by: Aaron Conole <aconole@redhat.com>
Signed-off-by: Michael Santana <msantana@redhat.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Luca Boccassi <bluca@debian.org>
Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Acked-by: Thomas Monjalon <thomas@monjalon.net>