Mining (Skills, Crafting, Stats, Sell Minerals, & Custom Models)

UPDATE

1. Added the ability to charge money for upgrading skills.
2. Config to enable/disable CH_Mining.Config.ShouldCostToUpgradeSkills
3. Config to determine price CH_Mining.Config.CostToUpgradeSkillPerLevel
4. The XP hud now longer shows on first join.
5. Maybe fixed a nil value error if player initially spawns with pickaxe in hand before database was finished loaded.