Updated test bootstrap

Current test failures are due to sebastian/version not reporting the correct
version when the lowest stable version is installed (1.0.4 of that package
corrected the issue). Since `test/bootstrap.php` was essentially unrequired at
this point, removing it in favor of using only the composer autoloader
simplifies dependencies while retaining the testing strategy.

Author: weierophinney

phpunit.xml.dist

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:noNamespaceSchemaLocation="./vendor/phpunit/phpunit/phpunit.xsd"
-         bootstrap="./test/bootstrap.php"
+         bootstrap="./vendor/autoload.php"
          colors="true">
     <testsuites>
         <testsuite name="zend-mvc Test Suite">