Avoid adding an empty line when headline has none.

org_dom/org_dom.py

@@ -515,6 +515,9 @@ def tokenize_contents(contents: str):
 
 
 def parse_contents(raw_contents: List[RawLine]):
+    if len(raw_contents) == 0:
+        return []
+
     contents_buff = []
     for line in raw_contents:
         contents_buff.append(line.line)
@@ -695,6 +698,7 @@ class OrgDom:
             last_type = ltype
             structured_lines.append(content)
 
+        if len(structured_lines) > 0:
             yield "".join(structured_lines)
 
         for child in headline.children:

tests/01-simple-2.org

@@ -14,9 +14,7 @@ First level content
 :PROPERTIES:
 :ID:       01-simple-second-level-id
 :END:
-
-   Second level content with no indentation
-
+Second level content with no indentation or space around
 *** Third level with no content
 **** Forth level
     :PROPERTIES: