[DotGNU]treecc: node hierarchy proof-of-concept

[nymia]

Here is sample output of treecc, which was modified, generated by walking
the node tree using /treecc/examples/ as test.

expression
  binary
    plus
    minus
    multiply
    divide
    power
  unary
    negate
  intnum
  floatnum
  cast
type_code
  error_type
  int_type
  float_type

This feature is good for viewing node hierarchies, like cscc, of which I'm
not very much familiar with. There are probably over 50 nodes in the .tc
files alone. So, a feature like it will help developers like me understand
the relationship among these nodes.

BTW, the code is only a proof-of-concept, it will change to target XML or
HTML documents. Let me know which document type is the preferred one.

See http://www.geocities.com/nymia20001/pnet/treecc/node_tree.html for more
details about the code and sample output.