Merge pull request #1 from openalea/master

Update from original
fixing setup in openalea.core
Update README.md
Merge pull request #105 from cokelaer/master

fixing setup to make sub-packages available
Fix #107
Merge pull request #111 from gbaty/fix_107

Fix #107
First draft to restore loader/saver approach.
Apply it to controls and part of Project
Project now use ProjectLoader for loading