Heroku Optimizers Buildpack

Add binaries for image optimization on Heroku.

Binaries in this buildpacks :

• advpng
• gifsicle
• jpegoptim
• jpegtran
• optipng
• pngcrush
• pngquant

Binaries are in this git repo in vendor/optimizers/

On compilation :

• Binaries are copied into vendor/optimizers
• Symlink to binaries is added to ensure next buildpacks will have binaries available
• vendor/optimizers is added to PATH through a .profile.d script
• Version of each binaries is displayed