The first proper update of the mod, adding more blocks as well as fixing things!

Note that I've bumped up the requirement to Forge 43.2.0+ to encourage using a stable environment.

• Added a snazzy new mod logo icon for mods menu.
• Added Cracked and Worn Castle Brick stairs, slabs, and walls.
• Added Cracked Underbrick stairs, slabs, and walls.
• Added Weathered Nagastone slabs, left and right.
• Castle Brick slabs and walls are now properly tagged as part of castle bricks thus Mazebreaker will be able to mine those properly.
• Towerwood Banister is now tagged as part of banisters block tags.