Added config for travis-ci auto-builds

This adds the .travis.yml file that tells Travis what and how to build.
See http://docs.travis-ci.com/user/build-configuration/ for docs on how
the directives in the file configure the build.

Added BUILD_KERNEL to Travis build spec

The Ubuntu 12.4 LTS images Travis uses run a kernel too old for the igb
library or module to build, so we need to build against an installed but
newer-than-running kernel. The BUILD_KERNEL option tells the module build
to use the alternate kernel source.

Add install of ethtool.h to system includes to Travis config

Again, the Ubuntu 12.4 LTS image has an old kernel's userspace API headers
installed in /usr/include/linux, and this copies one of the headers from
the newer kernel we're building against into the userspace API area.

Added libsndfile1-dev to Travis config for simple-listener build
Updated README from master and added Travis build status.

This includes an image that the Travis build server generates dynamically
whenever it performs a build. The result is an image in the main github
page for the branch which gives the current build status of the branch.
Merge pull request #96 from pinealservo/travis-ci-for-upstream

Travis ci for upstream
MRP: add cpputest and start of a test framework
mrpd: cpputest heading corrections in the copyright section
README.rst update for cmake
travis.yml fix for submodule updating
Merge pull request #95 from audioscience/cpputest

MRP: add cpputest and start of a test framework
Updated README from master and added Travis build status.