fix value = empty string
remove unscoped from item.rb
fix Item.all
remove unretired from item filter
fix retired checkbox
borrowable / unborrowable translations
change active to used in haml
remove default unretired = true from coffee controller
refactore unused / used param in model filter
refactor borrowable param in model filter
refactor Model.all and software filter in model filter
remove forgotten unretired from coffee controller
refactor / simplify / comment filters & inventory action
borrowable -> is_borrowable in haml
change index tabs filters
fix software filter not to include options