added BuildWP8 for msbuild
added BuildWP8 for msbuild

pwelter34/NLog,MartinTherriault/NLog,bhaeussermann/NLog,AndreGleichner/NLog,UgurAldanmaz/NLog,NLog/NLog,hubo0831/NLog,MoaidHathot/NLog,luigiberrettini/NLog,hubo0831/NLog,kevindaub/NLog,littlesmilelove/NLog,UgurAldanmaz/NLog,michaeljbaird/NLog,BrutalCode/NLog,littlesmilelove/NLog,MoaidHathot/NLog,tohosnet/NLog,nazim9214/NLog,ie-zero/NLog,tetrodoxin/NLog,sean-gilliam/NLog,tetrodoxin/NLog,BrutalCode/NLog,MartinTherriault/NLog,tohosnet/NLog,snakefoot/NLog,ie-zero/NLog,breyed/NLog,ilya-g/NLog,AndreGleichner/NLog,michaeljbaird/NLog,luigiberrettini/NLog,bryjamus/NLog,bryjamus/NLog,breyed/NLog,bhaeussermann/NLog,304NotModified/NLog,pwelter34/NLog,nazim9214/NLog,ilya-g/NLog,bjornbouetsmith/NLog,bjornbouetsmith/NLog,kevindaub/NLog