Treeview delay adding child

* add child once treeview expands
add label to assigned ressource template

Fix #347
Merge branch 'master' of github.com:Heigvd/Wegas

# By Francois-Xavier Aeberhard
# Via Francois-Xavier Aeberhard
* 'master' of github.com:Heigvd/Wegas:
  Fix share widget url
  Ortograph fix
  Fix #357