Update changelog for 1.6.4
Update changelog for 1.6.4

nicolas-grekas/composer,localheinz/composer,fabpot/composer,andrerom/composer,stefangr/composer,staabm/composer,naderman/composer,pierredup/composer,slbmeh/composer,composer/composer,alcohol/composer,milleruk/composer,vdm-io/composer,floverdevel/composer,johnstevenson/composer,stof/composer