V1.2 enlive visualizer added

Included is a separate function for enlive output. Next step would be to make tree-viz auto-detect output format and behave accordingly. 

I also believe the support functions could be substantially simplified. I quit when it worked.

Note that the require trick does not load rhizome on my system, where it is available. I have tested the code in my sandbox, where it generates correct output for at least the input "a(a)a" on the toy tree parser "tree: node* node: leaf | <'('> node (<'('> node <')'>)* node* <')'> leaf: #'a+' ".