Generator updates

Adds:

- new basic/default `Adaptor` and `Driver` classes for new generated modules.
- better generated `README`, now with better installation instructions and examples
- basic specs for new adaptors and drivers, and better namespacing for existing specs.


I'm not sure what should go into the generated `README` vs. what's only in our modules, so I didn't make too many changes. If more should be added by default, please let me know.


:candy: