Implement --fail-on-risky and --fail-on-warning commandline options as well as failOnRisky and failOnWarning configuration options

[sebastianbergmann]

Use exit(PHPUnit_TextUI_TestRunner::FAILURE_EXIT); instead of exit(PHPUnit_TextUI_TestRunner::SUCCESS_EXIT); when there are no test failures and no test errors but risky tests or tests with warnings.

[rentalhost]

The line 148 broked phpunit because doRun() on line 89 will call it with only two arguments, and $exit argument is required. The fix is just append a = false on this.

[sebastianbergmann]

@rentalhost So that is what #2094 was about. Thanks!