switch to building pngquant from source for travis
switch to building pngquant from source for travis
weheartit/image_optim,mihailim/image_optim,toy/image_optim,ramiroaraujo/image_optim,weheartit/image_optim,ramiroaraujo/image_optim,mihailim/image_optim,ramiroaraujo/image_optim,toy/image_optim,weheartit/image_optim,toy/image_optim,mihailim/image_optim