Refactoring: split up "Reducers" page

[markerikson]

The "Reducers" page has grown too large. I want to split it up, and also organize the existing content better.

Rough ideas:

• The "Reducer Utilities" category needs to be split into multiple categories. At a minimum, I would like categories for:
  • alternatives to the built-in combineReducers utility (such as the combineSectionReducers, combined-reduction, and topologically-combine-reducers)
  • Lookup table utilities (anything that's equivalent to the createReducer function in the "Reducing Boilerplate" page of the Redux docs)
  • Sequential composition (like reduce-reducers)
• Anything to do with dynamic reducer injection probably ought to go into a new page. I'm thinking a "Store - Code Splitting" page, similar to the existing "Store - Persistence" page. There may be some related libs scattered elsewhere throughout the list that ought to go into the "Code Splitting" page too.
• The "State Machines" section should probably go into a new "Reducers - Prebuilt Use Cases" page. (Or, then again, maybe it should be "Prebuilt Use Cases - Reducers"? Ditto for libs like redux-data-strucures - stuff that is more than just "combining" reducers in some way, but rather providing functionality out of the box.
• Might be good to extract a "Functional Composition" category, and put libs like redux-xforms, horux, and dextrous in there.

So, I've got ideas here, but I'm less sure of exactly what I want the final result to be. I know that people have said this page is intimidating and confusing, so I'm hoping to make it more useful.