Run autoprefixer after cssmin

The autoprefixer task in the build task has to be after the cssmin one, because it's cssmin which moves files from .tmp/concat/css to dist/css:

    Running "cssmin:generated" (cssmin) task
    Verifying property cssmin.generated exists in config...OK
    Files: .tmp/concat/css/vendor.css -> dist/css/vendor.css
    Files: .tmp/concat/css/main.css -> dist/css/main.css
    Options: report=false
    Reading .tmp/concat/css/vendor.css...OK
    Reading .tmp/concat/css/vendor.css...OK
    Writing dist/css/vendor.css...OK
    File dist/css/vendor.css created.
    Reading .tmp/concat/css/main.css...OK
    Reading .tmp/concat/css/main.css...OK
    Writing dist/css/main.css...OK
    File dist/css/main.css created.

The autoprefixer looks for files in the dist/css folder:

    Running "autoprefixer:dist" (autoprefixer) task
    Verifying property autoprefixer.dist exists in config...OK
    Files: dist/css/main.css -> dist/css/main.css
    Files: dist/css/vendor.css -> dist/css/vendor.css
    Options: diff=false, map=false, browsers=["last 2 versions"]
    Reading dist/css/main.css...OK
    Writing dist/css/main.css...OK
    File "dist/css/main.css" prefixed.
    Reading dist/css/vendor.css...OK
    Writing dist/css/vendor.css...OK
    File "dist/css/vendor.css" prefixed.
Merge pull request #111 from devantoine/patch-1

Run autoprefixer after cssmin