Adjusted css so that long metadata keys or values don't overlap other elements.
Adjusted some css so that metadata wraps rather that overlaps.  Added sorting to metadata keys that uses the user's locale.  Switched metadata editting to use a text area so that large amounts of metadata are easier to work with.  JSON objects within metadata are stringified for display and parsed on input.
Switched to using locale sorting.  Added a secondary sort field so users have a predicatable sort order if they have the same last name.
Added tests for adding, editing, and deleting metadata on an item.
Merge pull request #417 from girder/metadata-editing

Metadata editing