Shortens usings in dropwhile
Shortens usings in dropwhile

tempbottle/cppitertools,ryanhaining/cppitertools,jkhoogland/cppitertools,ryanhaining/cppitertools,tempbottle/cppitertools,jkhoogland/cppitertools,tempbottle/cppitertools,jkhoogland/cppitertools,ryanhaining/cppitertools