new option: --stop-on-failure
Merge branch 'stop-on-failure' of https://github.com/mpartel/paratest into mpartel-stop-on-failure
Merge branch 'stop-on-failure' of https://github.com/mpartel/paratest into mpartel-stop-on-failure

Conflicts:
	README.md
	functional/PHPUnitTest.php
	it/ParaTest/Runners/PHPUnit/RunnerIntegrationTest.php
	src/ParaTest/Console/Testers/PHPUnit.php
	src/ParaTest/Runners/PHPUnit/Options.php
	test/ParaTest/Console/Commands/ParaTestCommandTest.php
	test/ParaTest/Console/Testers/PHPUnitTest.php
	test/ParaTest/Runners/PHPUnit/SuiteLoaderTest.php
	test/fixtures/output/usage.txt