Improvements to the phpunit.xml.dist file

 - Fixes code coverage
 - Turns of color as this is not usefull in text-only output environments
 - Adds PHPUnit xsd
 - Makes @covers annotations manditory
 - Outputs code coverage to stdout
Improvements to Travis build file

 - Adds more PHP versions
 - Makes PHPUnit be run from the vendor directory
Fixes broken test