Added layer physics and mod config.

Cloth Config is now required!

Config:

• You can enable/disable the mod.
• You can enable/disable each block individually.
• At this moment, disabled blocks won't drop items. (This will be fixed in the next minor update)

Layer physics:

• Layered blocks now fall if not supported.
• Breaking a layered block with another layered block above it will cause the upper block to lose a layer instead.
• If a layered block is below a full layered block, they will swap positions.

New blocks with layered mining:

• Red sand
• Clay