Implement fuzzy matching

[jedmund]

Most users don't know the exact names of items. For those users, we should implement item "search" in the form of fuzzy matching.

This takes what they input ($g until jeanne) and presents them with a picker of all items in the database matching their querty (jeanne).

We don't want to build real search, but through clever queries we can probably get pretty close to a very good solution. The main thing to look out for is tuning both our query and our heuristics so that we show the right number of results, the right quality of results, and that we show results at the right time (i.e. not for exact matches).

[jedmund]

There are code samples in #45