Implement batched updates

No docs yet, more testing needed.

src/batch.luau

@@ -0,0 +1,23 @@
+if not game then script = require "test/relative-string" end
+
+local flags = require(script.Parent.flags)
+local throw = require(script.Parent.throw)
+local graph = require(script.Parent.graph)
+
+local function batch(setter: () -> ())
+    local already_batching = flags.batch
+
+    flags.batch = true
+
+    local ok, err: string? = pcall(setter)
+
+    flags.batch = false
+    
+    if not ok then throw(`error occured while batching updates: {err}`) end
+
+    if not already_batching then -- todo: flush anyways?
+        graph.flush_update_queue()
+    end
+end
+
+return batch