Added translation tags for labels on template pages
Added related transactions to account details page
Added links from transaction list to transaction detail page
Fixed typo related to transaction code
Added related transactions to purchaser details
Added fields and calculations to track accumulation (vs consumption) and expenses (vs income) for purchasers
Added Actions heading and copied delete button style from transaction list to account list
Clean up imports and some pep8 fixes
Added abstract base model Archivable, applied it to all models and included migration for the db.

This now allows you to hide old inventory items from the view without
making it necessary to delete them. Once you have 50 odd inventory
items and only two of them with stock it makes a lot of sense.