Improve TSSymbolExplorerPresenter to display number of children by fields

[jecisc]

In the TSSymbolExplorerPresenter, next to the field name, I now dispaly the min and max number of children I found in the node. This allows to know easily multiple things:

• If the node is optional
• If the node always has the same value
• If the node has an undefined number of values

Here is an example:

Info we can get fast:

• The name is an unique node
• The body is an unique node
• Superclasses are optional. Here I see a max number of 1 superclass but my sample was small and had 0 class with multiple inheritance
• The comments are optional

[jecisc]

I think failing tests are not related