Prune duplicate resolved font-family values (#217)

Author: nigelmegitt

src/main/js/html.js

@@ -1424,6 +1424,23 @@
 
                     }
 
+                    // prune later duplicates we may have inserted 
+                    if (rslt.length > 0) {
+
+                        var unique=[rslt[0]];
+
+                        for (var fi = 1; fi < rslt.length; fi++) {
+
+                            if (unique.indexOf(rslt[fi]) == -1) {
+
+                                unique.push(rslt[fi]);
+
+                            }
+                        }
+
+                        rslt = unique;
+                    }
+
                     dom_element.style.fontFamily = rslt.join(",");
                 }
         ),
@@ -1815,4 +1832,4 @@
 })(typeof exports === 'undefined' ? this.imscHTML = {} : exports,
         typeof imscNames === 'undefined' ? require("./names") : imscNames,
         typeof imscStyles === 'undefined' ? require("./styles") : imscStyles,
-        typeof imscUtils === 'undefined' ? require("./utils") : imscUtils);
+        typeof imscUtils === 'undefined' ? require("./utils") : imscUtils);