Fixed Non-ASCII attachment filename will crash when downloading.

Thanks to xet7 !

Fixes #2759

packages/wekan-cfs-data-man/tests/common.js

@@ -0,0 +1,38 @@
+// ab2str = function ab2str(buf) {
+//   return String.fromCharCode(new Uint8Array(buf));
+// }
+
+bin2str = function bin2str(bufView) {
+  var length = bufView.length;
+  var result = '';
+  for (var i = 0; i<length; i+=65535) {
+    var addition = 65535;
+    if(i + 65535 > length) {
+      addition = length - i;
+    }
+    try {
+      // this fails on phantomjs due to old webkit bug; hence the try/catch
+      result += String.fromCharCode.apply(null, bufView.subarray(i,i+addition));
+    } catch (e) {
+      var dataArray = [];
+      for (var j = i; j < i+addition; j++) {
+        dataArray.push(bufView[j]);
+      }
+      result += String.fromCharCode.apply(null, dataArray);
+    }
+  }
+  return result;
+};
+
+ab2str = function ab2str(buffer) {
+  return bin2str(new Uint8Array(buffer));
+};
+
+str2ab = function str2ab(str) {
+  var buf = new ArrayBuffer(str.length);
+  var bufView = new Uint8Array(buf);
+  for (var i=0, strLen=str.length; i<strLen; i++) {
+    bufView[i] = str.charCodeAt(i);
+  }
+  return buf;
+};