Clean repo for open source release

Remove build artifacts, dev tool configs, unused dependencies,
and third-party source dumps. Add proper README, update .gitignore,
clean up Makefile.

src/main/resources/assets/tiedup/models/item/ball_gag.json

@@ -0,0 +1,98 @@
+{
+  "parent": "minecraft:item/generated",
+  "textures": {
+    "layer0": "tiedup:item/ball_gag"
+  },
+  "overrides": [
+    {
+      "predicate": {
+        "custom_model_data": 1
+      },
+      "model": "tiedup:item/ball_gag_black"
+    },
+    {
+      "predicate": {
+        "custom_model_data": 2
+      },
+      "model": "tiedup:item/ball_gag_blue"
+    },
+    {
+      "predicate": {
+        "custom_model_data": 3
+      },
+      "model": "tiedup:item/ball_gag_brown"
+    },
+    {
+      "predicate": {
+        "custom_model_data": 4
+      },
+      "model": "tiedup:item/ball_gag_cyan"
+    },
+    {
+      "predicate": {
+        "custom_model_data": 5
+      },
+      "model": "tiedup:item/ball_gag_gray"
+    },
+    {
+      "predicate": {
+        "custom_model_data": 6
+      },
+      "model": "tiedup:item/ball_gag_green"
+    },
+    {
+      "predicate": {
+        "custom_model_data": 7
+      },
+      "model": "tiedup:item/ball_gag_light_blue"
+    },
+    {
+      "predicate": {
+        "custom_model_data": 8
+      },
+      "model": "tiedup:item/ball_gag_lime"
+    },
+    {
+      "predicate": {
+        "custom_model_data": 9
+      },
+      "model": "tiedup:item/ball_gag_magenta"
+    },
+    {
+      "predicate": {
+        "custom_model_data": 10
+      },
+      "model": "tiedup:item/ball_gag_orange"
+    },
+    {
+      "predicate": {
+        "custom_model_data": 11
+      },
+      "model": "tiedup:item/ball_gag_pink"
+    },
+    {
+      "predicate": {
+        "custom_model_data": 12
+      },
+      "model": "tiedup:item/ball_gag_purple"
+    },
+    {
+      "predicate": {
+        "custom_model_data": 14
+      },
+      "model": "tiedup:item/ball_gag_silver"
+    },
+    {
+      "predicate": {
+        "custom_model_data": 15
+      },
+      "model": "tiedup:item/ball_gag_white"
+    },
+    {
+      "predicate": {
+        "custom_model_data": 16
+      },
+      "model": "tiedup:item/ball_gag_yellow"
+    }
+  ]
+}