Start re-write radial tree. Bug with position.
Start the python version for trees. The alogrithms are new and will be our new base.
Algorithms for trees OK and fixed for all. Need to check radial.
Fix some bug with updates (do not modify the relative positions) and add the 'save' function.
Fix bugs with save/scrollbar and item position. The realsize gives the boundingRect of the tree (need to be renamed in boundingRect).
Fix known bugs. Version Ok (for now).