Update 2.9: Anti-flicker by fren_gor

This update adds an anti-flicker mechanism courtesy of fren_gor.

Please note that this feature is still somewhat experimental. Should you encounter any issues, please feel free to create an issue.

Update 2.8: STEPS! Different "animation rates" for SidebarStrings

View full changelog at https://www.spigotmc.org/resources/scoreboard-sidebar-api.21042/update?update=85406.