Enforce "en" lang in tests.

Some tests compare the result to english strings.

Do not test UnixCommandExecutor on Windows.

PharTest: explain why PHAR writing test are skipped.

InstallCommandTest: mock checkRequirements to allow the tests to run.

Run php_parallel_lint before all other tests.

Close #846

loggerconfig.php.example

@@ -1,5 +1,13 @@
 <?php
 
+/**
+ * PHPCI - Continuous Integration for PHP
+ *
+ * @copyright    Copyright 2014, Block 8 Limited.
+ * @license      https://github.com/Block8/PHPCI/blob/master/LICENSE.md
+ * @link         https://www.phptesting.org/
+ */
+
 return array(
     /** Loggers attached to every command */
     "_" => function() {