Replaces assert.h with cassert
Replaces assert.h with cassert

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