+ Fixed a mask bug that could take place in older versions.*
+ Added translation for "Completed!" text under challenges.
+ Allowed the advent calendar head to be changed in terms of texture and name.

* As far as I know, this is a CRAZY bug that comes at one point then can go instantly. Tested in three different 1.8.8 builds and these were the test results:

#1: No issue whatsoever.
#2: Came up but fixed itself.
#3: Partly fixed but not quite there.

Honestly I have no idea what's going on with it but if you don't plan on using masks, the plugin is fine to use. No harm is done to te server at all. The bug is that masks may not work when applied in survival mode but that's literally it. I will try my hardest to find a fix that works but I'm not quite there yet... cheers.