Leaves, partial

Logic is hopefully there, rendering is incorrect (it needs a color
handler).

Also, shit is going to happen w.r.t. "fancy graphics".

src/resources/assets/mmm/blockstates/materials/leaves/hevea.json

@@ -0,0 +1,8 @@
+{
+    "variants": {
+        "check_decay=false,decayable=false": { "model": "mmm:materials/leaves/hevea" } ,
+        "check_decay=false,decayable=true": { "model": "mmm:materials/leaves/hevea" } ,
+        "check_decay=true,decayable=false": { "model": "mmm:materials/leaves/hevea" } ,
+        "check_decay=true,decayable=true": { "model": "mmm:materials/leaves/hevea" }
+    }
+}

src/resources/assets/mmm/models/block/materials/leaves/hevea.json

@@ -0,0 +1,6 @@
+{
+    "parent": "minecraft:block/leaves",
+    "textures": {
+        "all": "mmm:blocks/materials/leaves/hevea"
+    }
+}

src/resources/assets/mmm/models/item/materials/leaves/hevea.json

@@ -0,0 +1,3 @@
+{
+    "parent": "mmm:block/materials/leaves/hevea"
+}