wip: kv rest api work

+ Range actions (get and delete)
+ Counter deletions

Take a look at any new TODOs as they most likely contain questions that I’ll probably just end up emailing the list about anyway :)
I came across this blog post: http://restful-api-design.readthedocs.org/en/latest/methods.html, which suggests using the Range: header on requests to indicate the range of resources to return. Another interesting resource I came across is: http://www.restapitutorial.com/media/RESTful_Best_Practices-v1_1.pdf

The last suggests using both range header and query parameters, allowing the query parameters to override the range header if both are supplied.