Fixed AppendVPrintf() handling for large strings.
Fixed AppendVPrintf() handling for large strings.

This caused a failure in server favicons.

jammet/MCServer,electromatter/cuberite,QUSpilPrgm/cuberite,mmdk95/cuberite,Frownigami1/cuberite,nichwall/cuberite,nounoursheureux/MCServer,nounoursheureux/MCServer,mc-server/MCServer,MuhammadWang/MCServer,linnemannr/MCServer,mc-server/MCServer,ionux/MCServer,guijun/MCServer,guijun/MCServer,guijun/MCServer,tonibm19/cuberite,HelenaKitty/EbooMC,jammet/MCServer,mc-server/MCServer,tonibm19/cuberite,Haxi52/cuberite,SamOatesPlugins/cuberite,Howaner/MCServer,mjssw/cuberite,kevinr/cuberite,marvinkopf/cuberite,MuhammadWang/MCServer,QUSpilPrgm/cuberite,Schwertspize/cuberite,linnemannr/MCServer,Frownigami1/cuberite,Fighter19/cuberite,birkett/MCServer,zackp30/cuberite,Haxi52/cuberite,zackp30/cuberite,marvinkopf/cuberite,QUSpilPrgm/cuberite,HelenaKitty/EbooMC,electromatter/cuberite,marvinkopf/cuberite,johnsoch/cuberite,jammet/MCServer,Tri125/MCServer,guijun/MCServer,HelenaKitty/EbooMC,birkett/cuberite,thetaeo/cuberite,nounoursheureux/MCServer,birkett/MCServer,nicodinh/cuberite,SamOatesPlugins/cuberite,kevinr/cuberite,johnsoch/cuberite,tonibm19/cuberite,tonibm19/cuberite,Howaner/MCServer,mjssw/cuberite,Fighter19/cuberite,Altenius/cuberite,mjssw/cuberite,nichwall/cuberite,nichwall/cuberite,mmdk95/cuberite,nevercast/cuberite,linnemannr/MCServer,mmdk95/cuberite,nounoursheureux/MCServer,thetaeo/cuberite,thetaeo/cuberite,Haxi52/cuberite,nevercast/cuberite,nevercast/cuberite,zackp30/cuberite,thetaeo/cuberite,jammet/MCServer,Haxi52/cuberite,nounoursheureux/MCServer,electromatter/cuberite,QUSpilPrgm/cuberite,nevercast/cuberite,electromatter/cuberite,mmdk95/cuberite,Tri125/MCServer,nevercast/cuberite,marvinkopf/cuberite,Schwertspize/cuberite,Schwertspize/cuberite,nicodinh/cuberite,zackp30/cuberite,guijun/MCServer,Schwertspize/cuberite,bendl/cuberite,kevinr/cuberite,electromatter/cuberite,nicodinh/cuberite,nichwall/cuberite,birkett/MCServer,birkett/cuberite,linnemannr/MCServer,mmdk95/cuberite,Tri125/MCServer,birkett/MCServer,Haxi52/cuberite,MuhammadWang/MCServer,mjssw/cuberite,Frownigami1/cuberite,Fighter19/cuberite,birkett/MCServer,zackp30/cuberite,Frownigami1/cuberite,Howaner/MCServer,ionux/MCServer,mc-server/MCServer,QUSpilPrgm/cuberite,birkett/cuberite,birkett/MCServer,SamOatesPlugins/cuberite,thetaeo/cuberite,bendl/cuberite,marvinkopf/cuberite,nichwall/cuberite,SamOatesPlugins/cuberite,Howaner/MCServer,marvinkopf/cuberite,Schwertspize/cuberite,Frownigami1/cuberite,MuhammadWang/MCServer,johnsoch/cuberite,SamOatesPlugins/cuberite,linnemannr/MCServer,HelenaKitty/EbooMC,guijun/MCServer,birkett/cuberite,nounoursheureux/MCServer,mc-server/MCServer,jammet/MCServer,johnsoch/cuberite,nicodinh/cuberite,Tri125/MCServer,Altenius/cuberite,bendl/cuberite,thetaeo/cuberite,ionux/MCServer,Howaner/MCServer,nevercast/cuberite,nicodinh/cuberite,MuhammadWang/MCServer,jammet/MCServer,Fighter19/cuberite,Altenius/cuberite,birkett/cuberite,tonibm19/cuberite,johnsoch/cuberite,kevinr/cuberite,nichwall/cuberite,tonibm19/cuberite,Tri125/MCServer,zackp30/cuberite,Haxi52/cuberite,electromatter/cuberite,QUSpilPrgm/cuberite,Altenius/cuberite,kevinr/cuberite,mjssw/cuberite,Fighter19/cuberite,nicodinh/cuberite,birkett/cuberite,ionux/MCServer,ionux/MCServer,Fighter19/cuberite,mmdk95/cuberite,ionux/MCServer,Tri125/MCServer,Howaner/MCServer,bendl/cuberite,mc-server/MCServer,kevinr/cuberite,bendl/cuberite,Altenius/cuberite,HelenaKitty/EbooMC,linnemannr/MCServer,mjssw/cuberite