Enable strict code coverage.
Ignore tests for scrutinizer build.
Remove redundant flags for phpunit.
Use shields.io flat svg badges.
Only specify the phpunit arguments that aren't in phpunit.xml.
Use phpcs as a library.
Remove --dev from composer install.

--dev is the default.
Merge pull request #3 from nubs/master

Update build scripts to use phpunit/phpcs as a library.