Delivers recursively a node and all of its children as a formatted string.
Child nodes and their elements are indented according to the following rules:
- Each pair (of label and value) is in its own line.
- Values containing sub elements (i. e. JSON objects and arrays) start in
the same line as the label.
- If they contain no or only one element they are written in the same
line, following directly after the label.
- If they contain more than one element the opening bracket is written into
the same line as the label, but each element in its own line. The
elements are indented further mTabWidth spaces. The closing bracket is
written in its own line, but in the same column as the opening bracket.