Implemented buying inventories.
Implemented inventory switching
Dont allow transfer items when source inventory = target inventory. Prevent this case.
Fix bug: shift click not correctly decolorising slot after emptying it.
Implemented some safeguards to prevent invalid amounts in crafting slots.
Fix a special case dupe bug this time explicitly and correctly.
Actually use the safeguard more often.
Fix crafting to be more stable and not to produce somehow damaged stacks, for example in transfer items. Fixed a bug occurring when producing multiple colored slots sharing a stack.