added support for gzip encoding
added support for gzip encoding

zhmz90/Images.jl,benmoran/Images.jl,timholy/Images.jl,rened/Images.jl,JuliaPackageMirrors/Images.jl,angi2/Images.jl,rened/Images.jl,benmoran/Images.jl,cdsousa/Images.jl,c42f/Images.jl,zhmz90/Images.jl,twadleigh/Images.jl,cdsousa/Images.jl,c42f/Images.jl,twadleigh/Images.jl,angi2/Images.jl