Update changelog; might have missed a few things
Update changelog; might have missed a few things

carsonreinke/rmagick,carsonreinke/rmagick,carsonreinke/rmagick,jonmartindell/rmagick,rmagick/rmagick,antonifs/rmagick,antonifs/rmagick,tvon/rmagick,jonmartindell/rmagick,mockdeep/rmagick,mockdeep/rmagick,btakita/rmagick,jonmartindell/rmagick,tvon/rmagick,btakita/rmagick,btakita/rmagick,rmagick/rmagick,rmagick/rmagick,tvon/rmagick,mockdeep/rmagick,mockdeep/rmagick,antonifs/rmagick