Fix #200 - Crash When Placing a Comparator Reading a Large Energy Storage

[aderoian]

Fixes #200

Changes

• Added ComparatorOutputProvider to standardizing getting a comparator value from a block entity
• RedstoneAddonBlockEntity.RedstoneControllable overrides ComparatorOutputProvider#getComparatorOutput and always returns 0 since only the redstone addon should be used to read comparator output.

Fix

Initial Cause: Invalid casting in SmallStorageBlock

We now cast to ComparatorOutputProvider since all block entities of a block with a comparator output should be its child. Since RedstoneAddonBlockEntity.RedstoneControllable overrides ComparatorOutputProvider#getComparatorOutput there is no longer an invalid cast.

[Rearth]

Great PR, thanks. Adding an interface to standardize this across entities is something I should've done much earlier already