Manual cash session opening and initial stock cost

This release includes two improvements:

• Manual open cash session: when requiring a cash session for POS is turned off, you can still open a session from the Journal tab (opening amount) so you can use the cash journal without blocking sales.
• Initial stock cost (valuation): on a product’s Cost history, use Set Cost on an ENTRY with no purchase document (e.g. migrated opening quantity). The unit cost is applied to that entry and to withdrawals until the next purchase entry, then valuation is recalculated.