Generalize the drawing functions of Data.Tree

[jonasc]

Hi,

I wanted to use drawTree on a Tree Int but it does not work for the drawing functions only accept Tree String instances. In my opinion this is too strict and can easily be generalized to Show s => Tree s. I made that change in a fork here: jonasc@e650dda
I would be happy to create a pull request for this commit.

[foxik]

@jonasc Good idea.

There needs to be no discussion about this change, it is a simple generalization, consistent with showTree and showTreeWith functions from {,Int}{Map,Set}.

Please create the pull request.

[foxik]

Merged to development branch quite a while ago.