Simpler, more powerful request action types

[jamesplease]

Right now there are 16 action types for requests. I think that can reduced to 4 while also preparing us for multi-operation requests at the same time.

Right now, for instance:

READ_RESOURCES_PENDING
READ_RESOURCES_SUCCEEDED

this could instead just be:

REQUEST_PENDING
REQUEST_SUCCEEDED

with a crudAction attribute. In the future, crudAction could possibly be an array supporting multiple types (although there would need to be a way to specify what resources are affected by what action).