Removed unneeded newlines from parsed comments

Newlines from comments separated by lines are retained when comments
are appended, so adding a newline between separate comments for a
node is not needed.

Author: cquammen

src/lib_json/json_reader.cpp

@@ -358,8 +358,6 @@ Reader::addComment(Location begin, Location end, CommentPlacement placement) {
     assert(lastValue_ != 0);
     lastValue_->setComment(std::string(begin, end), placement);
   } else {
-    if (!commentsBefore_.empty())
-      commentsBefore_ += "\n";
     commentsBefore_ += std::string(begin, end);
   }
 }

test/data/test_comment_02.json

@@ -9,7 +9,8 @@
    },
    // C++-style comment
    "cpp-test" : {
-      // Internal comment cpp-style
+      // Multiline comment cpp-style
+      // Second line
       "c" : 3,
       "d" : 4
    }