Trait and inheritance fixes

• Fix an issue when referencing a class from a trait (#9)
• Use the called class name instead to support test case inhertiance (#10)

Phar release (not signed)

• do not attempt to sign the published phar

Phar release

• start distributing the extension as a phar

Support for the Symfony 4.1 test service container

Merge pull request #4 from jakzal/symfony-4.1

Add support for the test service container from Symfony 4.1

Refresh the container when test case changes

New features:

• Refresh the container when test case changes

Bug fixes:

• Allow different sets of services (coming from different kernels) per test case class

Symfony support

• support for injecting services from a PSR-11 container to PHPUnit test cases
• support for service containers created by a Symfony kernel