remove DB::single
use primary_columns to get item_id from item
Bump DBIC dependency, avoid a regression causing test fails

Further discussion here: https://github.com/dbsrgits/dbix-class/pull/23#issuecomment-16001617
Merge pull request #10 from ribasushi/patch-1

Bump DBIC dependency, avoid a regression causing test fails
bump version to 0.24
fix bug in attempt to allow result source class methods for labels
remove DB::single
bump version to 0.25
also bump version in dist.ini
use 'unique' message in messages hashref. version to 0.26