[Phylobase-devl] path between two tips

[Thibaut Jombart]

Hi again,

here is another proposition of function. In fact, I would just make sure 
that it does not already exist somewhere before commiting. I wrote a 
function finding all the nodes on the shortest path from one tip to 
another. It could be part of the treewalk stuff.

My deepest problem now is with the function's name (advice welcome):
- path2tips
- tipsPath
- pathTips
- shortestPathBetweenTwoTips
- ...

Cheers,

Thibaut.