Support for PHPUnit 6

* Modify version constraints to allow the installation of PHPUnit 6.

* Add aliases for PHPUnit 6.

* Use an updated implementation of TestListener for PHPUnit 6

* Add an empty implementation for the
  method addWarning, added to the
  TestListener interface in PHPUnit6
* Load this implementation only if
  PHPUnit 6 is being used, otherwise use
  the current implementation

* Add shim for method setExpectedException

* For PHPUnit 5 forward the call to the parent class.
* For PHPUnit 6 use expectException, expectExceptionMessage, expectExceptionCode.

* Add shim file for loggers removed in PHPUnit 6

* Both the JSON and TAP loggers were removed in PHPUnit 6.

* Class name for exception is different for PHPUnit 6.

* Add missing setExpectedException method.

Added method to the following classes

* MysqlTest, PostgresTest, MongoDbTest and RedisTest

* Fix version constraint for the mock-objects package when using PHPUnit 4.8

* Check PHP version in shim.php.

When using PHP 5.6 class_exists returns true for 'PHPUnit\Framework\TestCase'.
PHUnit 6 can only be installed on PHP 7, now it's part of the main condition.

* Add phpunit5-loggers.php and the PHPUnit listener to Nitpick's ignore list.

* Fix class names in WebDriverTest use underscores instead of namespaces for PHPUnit classes.

* Replace namespaces with underscores.

* Added missing replacements.

* Use method setExpectedException instead of the annotations.

* testFailedSeeInPopup was using annotations that were conflicting with the exception thrown when a test is skipped.

* Add method addWarning to Listener instead of providing 2 different implementations

* Remove the path to this file from nitpick.json

* Change tests using setExpectedException  to inherit Codeception/Test/Unit.

* Remove duplicated method from all tests

* Use method_exists instead of class_exists

* Check if the method expectException is present.
* Use if statement instead of the && operator to call the other 2 methods.

* Fix versions range for PHPUnit related packages.

* Improve the readability of the condition to add the classes alias

* Remove extra space in version constraint.

* Add deprecation warning when using PHPUnit 6.

* Invert if statement to better match the comment description.

Author: MontealegreLuis

tests/unit/Codeception/Module/RedisTest.php

@@ -2,8 +2,9 @@
 
 use Codeception\Lib\ModuleContainer;
 use Codeception\Module\Redis;
+use Codeception\Test\Unit;
 
-class RedisTest extends \PHPUnit_Framework_TestCase
+class RedisTest extends Unit
 {
     /**
      * @var array