add separate sort order field to levels, so they can be reordered without changing the id and invalidating solutions

levels/00_zeroes.json

@@ -1,8 +0,0 @@
-{
-	"id": "00_zeroes",
-	"name": "Zeroes",
-	"description": "learn how to output data\nthis is a multi-line test",
-	"init_board": null,
-	"inputs": [],
-	"outputs": [0, 0, 0, 0, 0, 0, 0, 0]
-}

levels/01_cat.json

@@ -1,7 +1,8 @@
 {
-	"id": "01_cat",
+	"id": "intro_copy_input",
+	"sort_order": 12,
 	"name": "Copy Cat",
-	"description": "learn how to meow",
+	"description": "read input and output the same thing",
 	"init_board": null,
 	"inputs": [72, 101, 108, 108, 111, 44, 32, 119, 111, 114, 108, 103, 33],
 	"outputs": [72, 101, 108, 108, 111, 44, 32, 119, 111, 114, 108, 103, 33]

levels/01_loop.json

@@ -0,0 +1,9 @@
+{
+	"id": "intro_loop",
+	"sort_order": 11,
+	"name": "Loop",
+	"description": "repeated output",
+	"init_board": "o o\n   \n*P \n   \n   \n   ",
+	"inputs": [],
+	"outputs": [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+}

levels/01_zero.json

@@ -0,0 +1,9 @@
+{
+	"id": "intro_output",
+	"sort_order": 10,
+	"name": "Zero",
+	"description": "learn how to output data",
+	"init_board": "o o\n   \n*P \n   \n   \n   ",
+	"inputs": [],
+	"outputs": [0]
+}