Support ES6 Static Getters about react-docgen

[fkling]

If Im reading the docs right, this is simply a new resolver and the existing handlers can be reused?

Not quite. Resolvers just find component definitions. They don't extract any information. Handlers are functions which get passed the found component definitions and extract the information.

But also here, we tried to make everything transparent so that handlers don't have to care what kind of component definitions they get (class, stateless, etc).

However, looking at the code, this should already work for, for defaultProps at least. displayName needs to be updated to look into functions.