Make the unit test runable without requiring composer

Currently the unit tests fail if you don't install bugger via composer

```
Warning: require(/var/www/html/scott/tmp/bugger/tests/../vendor/autoload.php): failed to open stream: No such file or directory in /var/www/html/scott/tmp/bugger/tests/bootstrap.php on line 2

Fatal error: require(): Failed opening required '/var/www/html/scott/tmp/bugger/tests/../vendor/autoload.php' (include_path='.:/usr/share/pear:/usr/share/php') in /var/www/html/scott/tmp/bugger/tests/bootstrap.php on line 2
```

As the vendor directory isn't present if you don't use composer to install.

Start with tests/bootstrap.php, which currently requires vendor/autoload.php, and inspect how the unit tests are launched without Composer. Adjust the test setup so the suite can run when the vendor directory is absent, then verify that the unit tests no longer fail with the reported missing-file error.

Written by the indexing model from the issue text.