adds middleware to ensure page/per_page are present to requests

  - if page and per_page are in the params, this middleware will remove them and set them to env values
  - if page and per_page are missing, or evaluate to to 0 when to_i is run on them, then defaults are used.
  - per_page default value can be configured at the API level
  - page default is 1

refs #20
integrates mocha for mocks
w/s
adds per_page to DSL for configuring default per_page

refs #20
adds page/per_page methods that request handlers can access

refs #20