add a more realistic benchmark: a representer with 50 properties, a collection with 100 items, and that run 3x.
add code that would allow caching Binding instances. i am not sure if it makes sense to add this complexity, though, as it only gives a 0.006s/req boost whereas we add a cache and change internal api.
bindings now have the following naming schema (in line with populators, serializers, etc): Representable::Hash::Binding[::Collection].
move bindings, the file structure is now representable/hash/binding.rb.
add realistic benchmark.