gui: Add uncamel filter

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/4428
LGTM: imsodin, calmh

gui/default/syncthing/core/uncamelFilter.js

@@ -0,0 +1,27 @@
+angular.module('syncthing.core')
+    .filter('uncamel', function () {
+        return function (input) {
+            input = input.replace(/(.)([A-Z][a-z]+)/g, '$1 $2').replace(/([a-z0-9])([A-Z])/g, '$1 $2');
+            var parts = input.split(' ');
+            var lastPart = parts.splice(-1)[0];
+            switch (lastPart) {
+                case "S":
+                    parts.push('(seconds)');
+                    break;
+                case "M":
+                    parts.push('(minutes)');
+                    break;
+                case "H":
+                    parts.push('(hours)');
+                    break;
+                case "Ms":
+                    parts.push('(milliseconds)');
+                    break;
+                default:
+                    parts.push(lastPart);
+                    break;
+            }
+            input = parts.join(' ');
+            return input.charAt(0).toUpperCase() + input.slice(1);
+        };
+    });