feat(service): add option to customize the nested delimiter

```js
// will change the default '.' to '_'
$translateProvider.nestedObjectDelimeter('_');
```

Relates #1171

src/service/translate.js

@@ -36,7 +36,7 @@ function $translate($STORAGE_KEY, $windowProvider, $translateSanitizationProvide
       $notFoundIndicatorRight,
       $postCompilingEnabled = false,
       $forceAsyncReloadEnabled = false,
-      NESTED_OBJECT_DELIMITER = '.',
+      $nestedObjectDelimeter = '.',
       loaderCache,
       directivePriority = 0,
       statefulFilter = true,
@@ -261,6 +261,26 @@ function $translate($STORAGE_KEY, $windowProvider, $translateSanitizationProvide
     return this;
   };
 
+  /**
+   * @ngdoc function
+   * @name pascalprecht.translate.$translateProvider#nestedObjectDelimeter
+   * @methodOf pascalprecht.translate.$translateProvider
+   *
+   * @description
+   *
+   * Let's you change the delimiter for namespaced translations.
+   * Default delimiter is `.`.
+   *
+   * @param {string} delimiter namespace separator
+   */
+  this.nestedObjectDelimeter = function (delimiter) {
+    if (!delimiter) {
+      return $nestedObjectDelimeter;
+    }
+    $nestedObjectDelimeter = delimiter;
+    return this;
+  };
+
   /**
    * @name flatObject
    * @private
@@ -286,10 +306,10 @@ function $translate($STORAGE_KEY, $windowProvider, $translateSanitizationProvide
       if (angular.isObject(val)) {
         flatObject(val, path.concat(key), result, key);
       } else {
-        keyWithPath = path.length ? ('' + path.join(NESTED_OBJECT_DELIMITER) + NESTED_OBJECT_DELIMITER + key) : key;
+        keyWithPath = path.length ? ('' + path.join($nestedObjectDelimeter) + $nestedObjectDelimeter + key) : key;
         if(path.length && key === prevKey){
           // Create shortcut path (foo.bar == foo.bar.bar)
-          keyWithShortPath = '' + path.join(NESTED_OBJECT_DELIMITER);
+          keyWithShortPath = '' + path.join($nestedObjectDelimeter);
           // Link it to original path
           result[keyWithShortPath] = '@:' + keyWithPath;
         }
@@ -1558,6 +1578,20 @@ function $translate($STORAGE_KEY, $windowProvider, $translateSanitizationProvide
         return $cloakClassName;
       };
 
+      /**
+       * @ngdoc function
+       * @name pascalprecht.translate.$translate#nestedObjectDelimeter
+       * @methodOf pascalprecht.translate.$translate
+       *
+       * @description
+       * Returns the configured delimiter for nested namespaces.
+       *
+       * @return {string} nestedObjectDelimeter
+       */
+      $translate.nestedObjectDelimeter = function () {
+        return $nestedObjectDelimeter;
+      };
+
       /**
        * @ngdoc function
        * @name pascalprecht.translate.$translate#fallbackLanguage

test/unit/service/translate.spec.js

@@ -123,6 +123,17 @@ describe('pascalprecht.translate', function () {
       });
     });
 
+    describe('$translate#nestedObjectDelimeter()', function () {
+
+      it('should be a function', function () {
+        expect(typeof $translate.nestedObjectDelimeter).toBe('function');
+      });
+
+      it('should return \'.\' if no delimiter is specified', function () {
+        expect($translate.nestedObjectDelimeter()).toEqual('.');
+      });
+    });
+
     it('should return a promise', function () {
       expect($translate('FOO').then).toBeDefined();
       expect(typeof $translate('FOO').then).toEqual('function');
@@ -304,6 +315,23 @@ describe('pascalprecht.translate', function () {
     });
   });
 
+  describe('$translate#nestedObjectDelimeter()', function () {
+
+    beforeEach(module('pascalprecht.translate', function ($translateProvider) {
+      $translateProvider.nestedObjectDelimeter('_');
+    }));
+
+    var $translate;
+
+    beforeEach(inject(function (_$translate_) {
+      $translate = _$translate_;
+    }));
+
+    it('should return \'_\' if such delimiter is specified', function () {
+      expect($translate.nestedObjectDelimeter()).toEqual('_');
+    });
+  });
+
   describe('$translate#use()', function () {
 
     beforeEach(module('pascalprecht.translate', function ($translateProvider) {