fix prismarine stairs

Sorry for the noise in mc_id.h, but somebody decided they want DOS
line endings and I couldn't allow that to happen. When not doing that
put the whole thing into diff, I decided to just fix the indentation
too while I was at it.

Needed bugfixing of some overlooked unsigned char usages for block IDs,
as otherwise the lighting would be scuffed.

Concerns issue #1486.

overviewer_core/src/block_class.c

@@ -76,7 +76,9 @@ const mc_block_t block_class_stair[] = {
 	block_acacia_stairs,
 	block_dark_oak_stairs,
 	block_red_sandstone_stairs,
-	block_purpur_stairs
+	block_purpur_stairs,
+	block_prismarine_stairs,
+	block_dark_prismarine_stairs
 };
 const size_t block_class_stair_len = COUNT_OF(block_class_stair);
 
@@ -134,6 +136,8 @@ const mc_block_t block_class_ancil[] = {
 	block_dark_oak_stairs,
 	block_red_sandstone_stairs,
 	block_purpur_stairs,
+	block_prismarine_stairs,
+	block_dark_prismarine_stairs,
 	block_grass,
 	block_flowing_water,
 	block_water,
@@ -175,6 +179,8 @@ const mc_block_t block_class_alt_height[] = {
 	block_acacia_stairs,
 	block_dark_oak_stairs,
 	block_red_sandstone_stairs,
+	block_prismarine_stairs,
+	block_dark_prismarine_stairs,
 	block_stone_slab2,
 	block_purpur_stairs,
 	block_purpur_slab,