extract the redis worker cache into a separate npm

[mwawrusch]

With regards to the proposed minimalism it makes sense to decouple the redis worker cache from the project and move it into it's own NPM. Some of us (e.g I :-)) want to add a mongodb store as a first class citizen.

[indexzero]

When I see neuron-mongodb I will consider this :) ... let me know if there are other hooks you need to get this working.

[dtex]

@mwawrusch Does this still interest you? I wouldn't mind a nueron-leveldb myself