Fixed reported Mei bugs

In this commit, I also changed Mei's authorship credit from "Arndress, Mei-enthusiast, Master_Ultimus, humdumthrow" to simply "Arndress". Mei's initial development was on an online text document that anyone could edit, meaning that anyone could drop a line here or there. It also meant that anybody could claim author credit with very little work done. I can attest that I personally wrote almost all of Mei's dialogue. The thee names above contributed a combined total of less than 50 lines. I also mentioned this balance in the subreddit post when Mei hit testing.

humdumthrow retains his artist credit for his original model. He also did the posing, except for "iceblock" and "adjusting", which were done by UnderscorM3.