v2.0.0

This is a cleanup / bugfix release, bringing the minimum required version of RGBDS to 0.5.1, brought to you by @Rangi42!
It fixes many minor bugs, so they won't be listed here.

This project is now in maintenance mode; don't expect any new major updates.
Please keep an eye on gbdev/rgbds#98, which should see this macro pack's functionality natively supported by RGBASM in the near future.