Add resource_tool and random_tool

random_tool.gd

@@ -0,0 +1,12 @@
+tool
+
+# Tools for randomization
+
+static func pick(array):
+	""" Pick a random item in an array
+	"""
+	if array.size():
+		# TODO more uniform method
+		return array[randi() % array.size()]
+	else:
+		return null

resource_tool.gd

@@ -0,0 +1,22 @@
+tool
+
+# Resources tools
+
+static func list_from_dir(path: String, pattern="*") -> PoolStringArray:
+	""" List all resources in a directory (non-recursive)
+	"""
+	var result := PoolStringArray()
+
+	path = path.rstrip("/")
+	var dir := Directory.new()
+	if dir.open(path) == OK:
+		dir.list_dir_begin()
+		var file_name := dir.get_next()
+		while file_name != "":
+			if file_name.match(pattern) and not dir.current_is_dir():
+				result.append(path + "/" + file_name)
+			file_name = dir.get_next()
+	else:
+		push_error("Can't read directory: %s" % path)
+
+	return result