Initial commit. Implement music sync features.

chart/test_nibelungen/audio.mp3.import

@@ -0,0 +1,19 @@
+[remap]
+
+importer="mp3"
+type="AudioStreamMP3"
+uid="uid://btmy8ffph5gn3"
+path="res://.godot/imported/audio.mp3-a6ce572dbede3712a85c3e444692049c.mp3str"
+
+[deps]
+
+source_file="res://chart/test_nibelungen/audio.mp3"
+dest_files=["res://.godot/imported/audio.mp3-a6ce572dbede3712a85c3e444692049c.mp3str"]
+
+[params]
+
+loop=false
+loop_offset=0
+bpm=0
+beat_count=0
+bar_beats=4

chart/test_nibelungen/tempo.tres

@@ -0,0 +1,9 @@
+[gd_resource type="Resource" script_class="Tempo" load_steps=2 format=3 uid="uid://b34uhnkvwfyc1"]
+
+[ext_resource type="Script" uid="uid://c3vwmf1f1woo3" path="res://resource_type/tempo.gd" id="1_yhdoo"]
+
+[resource]
+script = ExtResource("1_yhdoo")
+bpms = Array[float]([160.0, 222.0, 200.0, 190.0, 170.0, 150.0, 135.0])
+lengths = Array[float]([51.0, 638.0, 640.0, 641.0, 642.0, 644.0])
+metadata/_custom_type_script = "uid://c3vwmf1f1woo3"