Fix the add-new-tree function #2
Forgot to commit litterfall.py last time--in litterfall.py I implemented a method to get a tree from their oid
Add the animation effect, so that when the row for new sub-tree appears, the document moves to the newly created row
Merge branch 'master' of https://github.com/Swarthmore/litterfall

Merging--why is it necessary? I don't know...