Handle gltf binary

[ Ignore and Warn | Extract Textures (default) | Optimize Loading Embedded as Basisu ]

Enable compressed mip maps from Basis Universal for faster compressions.

Increase the quality of Basis to avoid corruption.

To keep compatibility use the first mip of the previous internal Godot format.

Because texture names may have invalid filename characters, adds String::validate_filename to sanitize filenames for import pipeline use.

doc/classes/String.xml

@@ -1002,6 +1002,12 @@
 				[/codeblocks]
 			</description>
 		</method>
+		<method name="validate_filename" qualifiers="const">
+			<return type="String" />
+			<description>
+				Replace all characters that are not allowed in [method is_valid_filename] with underscores.
+			</description>
+		</method>
 		<method name="validate_node_name" qualifiers="const">
 			<return type="String" />
 			<description>