Charcoal forge should be less finicky:

• Create from 7 or 8 charcoal
• Create from a coal block (this may not be worth implementing, as it just leads to complications with triggers, i.e. can't hook into onBlockActivated of the forge)

Additional fixes:

• Charcoal forge creation in BlockCharcoalPile needs to check multiblock conditions for lighting
• Forge should use proper multiblock for side conditions