0.21.0

Added

• Added support for vibrato in agb-tracker's XM format
• Method to stop the tracker

Changed

• agb-tracker now has an agb feature which you must enable to use it with agb. You won't notice
  unless you've been using default-features = false in which case we recommend removing that from your Cargo.toml.

Fixed

• There are no longer gaps between tiles in affine graphics modes.

Added

• Added option to export imported background graphics from include_background_gfx as pub.