Removes include of filter.hpp, CAPS include guards
Removes include of filter.hpp, CAPS include guards

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