Mark exact spawn tile of Tremor Worm

Issue: #311

Author: mathiasbynens

data/markers.json

@@ -36609,6 +36609,13 @@
 		"y": 32731,
 		"z": 13
 	},
+	{
+		"description": "Tremor Worm (spawn location)",
+		"icon": "star",
+		"x": 33393,
+		"y": 31955,
+		"z": 13
+	},
 	{
 		"description": "Mahatheb (exact spawn tile)",
 		"icon": "crossmark",
@@ -36630,13 +36637,6 @@
 		"y": 31808,
 		"z": 13
 	},
-	{
-		"description": "Tremor Worm (possible location)",
-		"icon": "star",
-		"x": 33397,
-		"y": 31940,
-		"z": 13
-	},
 	{
 		"description": "Levitate spot",
 		"icon": "red right",
@@ -36658,13 +36658,6 @@
 		"y": 32377,
 		"z": 13
 	},
-	{
-		"description": "Tremor Worm (possible location)",
-		"icon": "star",
-		"x": 33419,
-		"y": 31948,
-		"z": 13
-	},
 	{
 		"description": "North Teleport",
 		"icon": "flag",
@@ -36693,13 +36686,6 @@
 		"y": 32447,
 		"z": 13
 	},
-	{
-		"description": "Tremor Worm (possible location)",
-		"icon": "star",
-		"x": 33430,
-		"y": 31936,
-		"z": 13
-	},
 	{
 		"description": "Commemorative platinum coin",
 		"icon": "star",
@@ -36728,13 +36714,6 @@
 		"y": 31629,
 		"z": 13
 	},
-	{
-		"description": "Tremor Worm (possible location)",
-		"icon": "star",
-		"x": 33450,
-		"y": 31965,
-		"z": 13
-	},
 	{
 		"description": "Levitate spot",
 		"icon": "red left",
@@ -36777,13 +36756,6 @@
 		"y": 31188,
 		"z": 13
 	},
-	{
-		"description": "Tremor Worm (possible location)",
-		"icon": "star",
-		"x": 33469,
-		"y": 31952,
-		"z": 13
-	},
 	{
 		"description": "",
 		"icon": "flag",
@@ -36798,34 +36770,13 @@
 		"y": 32334,
 		"z": 13
 	},
-	{
-		"description": "Tremor Worm (possible location)",
-		"icon": "star",
-		"x": 33487,
-		"y": 31936,
-		"z": 13
-	},
-	{
-		"description": "Tremor Worm (possible location)",
-		"icon": "star",
-		"x": 33510,
-		"y": 31943,
-		"z": 13
-	},
 	{
 		"description": "Earl Osam, Cormaya",
 		"icon": "checkmark",
 		"x": 33518,
 		"y": 31439,
 		"z": 13
 	},
-	{
-		"description": "Tremor Worm (possible location)",
-		"icon": "star",
-		"x": 33518,
-		"y": 31963,
-		"z": 13
-	},
 	{
 		"description": "",
 		"icon": "up",