from_dict: option to create root ConfigTree

Addresses issue #137

pyhocon/config_parser.py

@@ -94,7 +94,7 @@ def parse_string(content, basedir=None, resolve=True):
         return ConfigParser().parse(content, basedir, resolve)
 
     @classmethod
-    def from_dict(cls, dictionary):
+    def from_dict(cls, dictionary, root=False):
         """Convert dictionary (and ordered dictionary) into a ConfigTree
         :param dictionary: dictionary to convert
         :type dictionary: dict
@@ -104,7 +104,7 @@ def from_dict(cls, dictionary):
 
         def create_tree(value):
             if isinstance(value, dict):
-                res = ConfigTree()
+                res = ConfigTree(root = root)
                 for key, child_value in value.items():
                     res.put(key, create_tree(child_value))
                 return res