make oPath cache the marks associated with it
make oPath cache the marks associated with it

This is mainly for performance reasons. Calculating the marks anew
everytime oPath#MarkNames() is called greatly increases the rendering
time of the tree. It trippled it for just a handful of marks...

nywilken/dotfiles,tschundler/dotfiles,tschundler/dotfiles,iff/dotfiles-old,iff/dotfiles-old,nywilken/dotfiles,tschundler/dotfiles