Merge pull request #2611 from liqd/2016-08-tb-iconfont-cachebust-2

restore cache busting for font-url

Author: 2e2a

src/adhocracy_frontend/adhocracy_frontend/static/stylesheets/scss/general/_mixins.scss

@@ -62,5 +62,5 @@ $rem-px-only: false !default;
 }
 
 @function font-url($path) {
-    @return url("../fonts/" + $path);
+    @return url("../fonts/" + $path + "?" + cachebust());
 }

src/adhocracy_frontend/checkcode_and_compile.cfg

@@ -164,6 +164,7 @@ inline =
             "grunt-htmlhint": "0.9.12-fix",
             "mailparser": "0.5.3",
             "ini": "1.3.4",
+            "node-sass": "3.8.0",
             "grunt-sass": "1.1.0",
             "grunt-sass-lint": "0.2.0"
         }
@@ -313,6 +314,8 @@ update-command = ${javascript:command}
 [gruntfile]
 recipe = collective.recipe.template
 inline =
+    var sass = require("node-sass");
+
     module.exports = function(grunt) {
         grunt.initConfig({
             ngtemplates: {
@@ -388,7 +391,12 @@ inline =
             sass: {
                 options: {
                     sourceMap: true,
-                    outputStyle: "compressed"
+                    outputStyle: "compressed",
+                    functions: {
+                        "cachebust": function() {
+                            return new sass.types.String("" + Date.now());
+                        }
+                    }
                 },
                 dist: {
                     files: {