In PhpStorm, I've got an issue with path resolution for the bootstrap file.
I don't know why the path in which Behat runs is always the folder `features`.
So Behat always fails trying to look for `/project/root/path/features/config/bootstrap.php`.
With this fix, bootstrap file will be resolved based on the base path.
Plus, people will be allowed to use the parameter `%paths.base%` to define a custom bootstrap file path.
E.g.:
```yaml
default:
extensions:
FriendsOfBehat\SymfonyExtension:
bootstrap: '%paths.base%/custom/bootstrap.php'
```
