Extracted container behaviors into a separate Container object.
Adds pagination to Containers#all by adding a PaginatedContainers class
that delegates to its contained Array of container data but supports a
Allows the page size for the "next page" to be overridden.

TODO: Still need to wrap the results from Containers#all in an Array of
Container objects (which are still TBD).
Updates to VCR cassettes for Containers extraction and pagination of containers.
Get rid of embarassing 'your code here'
An API call for all of the objects in a container should originate from
a `Container` object proxying for the specific container and not a
`Containers` object proxying for all of the user's containers.
* Extracted `File` abstraction
* Extracted pagination into an abstract class
* Containers and Files are now paginated
Improved docs
Defined a simple class-method DSL for PaginatedCollection
Replaces #all with #list (I blame @smashwilson)
Merge pull request #1 from elight/extract_containers

Extract containers