Phing build and release process
Introduced a Phing build configuration to help with the automatic building and testing of the client, as well as the release process.
In composer.json: cleaned up requirements, added a version, and provided an actual namespace for "psr-4" (composer warns against an empty namespace declaration). Commited composer.lock file to repository.
Cleaned up README documentation for obtaining the client via Composer. Removed section about manual install, as this client requires the autoloading capabilities of Composer. Added release documentation.
Renamed cbsIntegrationTest to cbsTechstoreClientIT so that PHPUnit does not pick up on it when running unit tests.
Cleaned up .gitignore file and deleted reports/phpunit.xml, as it should not have been commited to the repository.