Added a Paginator object for yielding paged results of a Cursor
Merge pull request #127 from JohnBrodie/master

Fix off-by-one error in schema_document
find_and_modify returns None if the query fails
tests the find_and_modify fix
Merge pull request #128 from a1gucis/bugfix-find-and-modify

Bugfix find and modify
Merge pull request #103 from jarrodb/master

Paginator object for yielding paged results of a Cursor