Update WoW Plugin to build 19034

Update WoW plugin, including switching to 128-bit GUIDs, which I've naively done with a structure containing two 64-bit integers instead. There's probably a nicer way to do this.

Same deal as last time I updated it, the values in debug printf()s look correct, but I lack the ability to build a .dll that works on anyone's machine but my own, so I can't test it myself until the build server builds me a DLL. :(

Also, Blizzard pushed out a minor patch while I was working on it, that's why the branch name is incorrect.