Revert "Merge pull request #148 from dimagi/revert-items"

This reverts commit 08151bc1733cb3f94058e3842a6d2fecac55c9bc, reversing
changes made to 0dc7f8e517043e586aabc23f95f3ef4eceb6df71.
make items an optional parameter, and fix tests
Merge pull request #161 from dimagi/items

Items