Support for Backlytra for 1.8.9

[vico93]

Hi!

In the first release for 1.9, you describe adding "Dragons will fly together with their owners that glide with Elytras."

There is a mod called Backlytra which adds Elytras for 1.8.9 (and the 1.10 sounds for both 1.8.9 and 1.9).

Is possible to release a late version of 1.8.9 with support from this? Would be amazing to be followed by a dragon while wearing a elytra. Another thing would be util to ship is the NullPointerException fix in EntityAIDragonCatchOwner added in latest version of 1.9, if the bug is applicable in 1.8.9.

Thanks in advance!