Add a docker/fig based build.
Use shields.io for the badge.
Add badges for packagist.
Specify the testsuite in the phpunit.xml.

This is done so that it doesn't have to be specified on the phpunit
command line.
Update PHPUnit to 4.x series.
Enable strict code coverage.
Remove --dev from composer install.

composer install installs dev dependencies by default.
Convert usage of phpunit to a library.

This interface is more programmatic and easier to handle code coverage
report for.
Convert usage of phpcs to a library.
Add php 5.6 to the travis build.