Changed log

Add php-7.3 test during Travis CI build.
Removing unused composer config on before_script step during Travis CI build work.
Using the assertCount to assert expected count is same as result.
Using the assertFileExists to assert file is existed.
Using the PHPUnit fixture method is protected function setUp().
To support future PHPUnit version, using the PHPUnit class namespace instead.
Upgrading to the final PHPUnit 4.x version.

matomo-org / component-decompress