Simplify drivers: We should get rid of interfaces. Hassles outweigh benefits.

[thomaslima]

Interfaces were implemented to facilitate sharing notebooks between labs, but in practice it is easier to manipulate notebooks rather than confuse everyone about why we are using meta classes. I propose to get rid of it.

Another observation: most users of lightlab are actually developers. So we need to decrease the barrier for new contributors. More helper functions, less templates. More examples, less subclassing.