PHPUnit 7 support (#4799)

* changed build process for phar

* added phpunit7 support

* Appveyor.yml to specify php 7.1 and PhpBrowserTest fixes (#4807)

* Update appveyor.yml to specify php version 7.1

Pull request #4799 fails due to AppVeyor and Chocolatey installing PHP 7.2 and not constrained to any version. This entire file assumes PHP 7.1, so I added what I believe is the constraint for Chocolatey/cist. 

Disclaimer: I am not familiar with Chocolatey or AppVeyor so I'm kind of taking a stab in the dark, well an educated guess have you.

* Update PhpBrowserTest.php

codeception.com forces https, assertion corrected.

* Updated redirect test in favor of http

Due to issue with TravisCI with php-curl/ssl, changed to this for better solution. travis-ci/travis-ci#6339

* Updated TravisCI composer configuration

TravisCI should test latest minor SemVer of Symfony packages not lowest, this was the only test failing due to memory overload from Composer trying to resolve dependencies.

Author: DavertMik

tests/unit/Codeception/Module/PhpBrowserTest.php

@@ -280,9 +280,9 @@ public function testLocationHeaderDoesNotRedirectWhenStatusCodeIs201()
 
     public function testRedirectToAnotherDomainUsingSchemalessUrl()
     {
-        $this->module->amOnUrl('http://httpbin.org/redirect-to?url=//codeception.com/');
+        $this->module->amOnUrl('http://httpbin.org/redirect-to?url=//example.org/');
         $currentUrl = $this->module->client->getHistory()->current()->getUri();
-        $this->assertSame('http://codeception.com/', $currentUrl);
+        $this->assertSame('http://example.org/', $currentUrl);
     }
 
     public function testSetCookieByHeader()