Feeds and Collections

(I'm making this a pull request to document some of the changes)

__new__
 * `PyPump.me` Person object for the logged in user
 * `Person.followers` feed of followers
 * `Person.following` feed of followings
 * `Person.lists` feed of collections
  * `Person.lists.create(title, content=None`) Create a new Collection
 * `Collection`:
  * `Collection.members` feed of Collections' members
  * `Collection.add(Person)` add a Person object to Collection
  * `Collection.remove(Person)` remove a Person object from Collection
  * `Collection.delete()` Delete collection

__changed__
 * `model.{comments, shares, likes}` are now iterable feeds

__moved__
 * `PyPump.Followers` moved to `Person.followers`
  * use `Note.to = PyPump.me.followers` instead of the old `Note.to = PyPump.Followers`
 * `PyPump.Following` moved to `Person.following`
 * `PyPump.List` moved to `Person.lists` (List class is now Collection class)

__bugs__
 * most likely