Directory support

[Odaeus]

A colleague introduced me to Spinach recently, am loving it over Cucumber!

I was wondering if a patch to add support for directories for steps would be welcome? So the Feature class name generator takes the path of the file into account and adds a namespace to the generated Steps class. This would allow me to group features together under categories relevant to the application and have it match the location of the Steps classes.

Currently it seems you can have Features in directories but the Steps classes are always top-level, let me know if it it's already supported!