HTML5 issues; wasm filename, slow loading

The HTML5 export was looking for 'v0.wasm' instead of 'v0.0621.wasm'.
Additionally itch.io wants the html file named 'index.html'. I've just
renamed the file to 'turbofat.html' for now, and the extra rename is a
manual step.

The HTML5 export was taking about 5 seconds to load, because it was only
loading one resource every frame. I've changed it to load as many
resources as it can in 0.1 seconds, as a compromise between speed and
responsiveness.

export_presets.cfg.template

@@ -109,7 +109,7 @@ custom_features=""
 export_filter="all_resources"
 include_filter="*.json"
 exclude_filter="src/test/*, src/demo/*, assets/test/*, assets/demo/*"
-export_path="export/html5/turbofat-html5-v##VERSION##.html"
+export_path="export/html5/turbofat.html"
 patch_list=PoolStringArray(  )
 script_export_mode=1
 script_encryption_key=""

src/main/resource-cache.gd

@@ -14,6 +14,8 @@ signal finished_loading
 # number of threads to launch; 1 is slower, but more than 4 doesn't seem to help
 const THREAD_COUNT := 4
 
+const CHUNK_SECONDS := 0.1
+
 # enables logging paths and durations for loaded resources
 export (bool) var _verbose := false
 
@@ -63,8 +65,10 @@ func start_load() -> void:
 
 func _process(delta: float) -> void:
 	if OS.has_feature("web") and _remaining_resource_paths:
-		# Web targets do not support background threads, so we load resources one at a time
-		_preload_next_png()
+		var start_usec := OS.get_ticks_usec()
+		# Web targets do not support background threads, so we load a few resources every frame
+		while _remaining_resource_paths and OS.get_ticks_usec() < start_usec + 1000000 * CHUNK_SECONDS: 
+			_preload_next_png()
 
 
 func _exit_tree() -> void: