Ajout de la branche bf-workspace
Update the item_instance loaders to use the new image pool.
Updates bf::item_field_edit to use the new image pool.

The new class is_visual_type is used to metaprogramatically select the functions
related to the visual data types (sprites, animations).
Correction de animation-editor [terminé].
Correction de model-editor.
L'éditeur d'animation fonctionne
Correction du model-éditor
The name of the default workspace can be given to the editor with the --workspace option.
Ajout d'un item_class_pool dans workspace_environment
Les membre de workspace_environment sont privés
Merge branch 'bf-workspace' of github.com:j-jorge/bear into bf-workspace
Compilation de l'éditeur de niveau
Petites modifs anciennes
item_class_pool cannot be copied nor assigned.
The workspace_environment uses smart pointers to store the image and item class pools.
Use forward declarations for workspace_environment.

ingame_view_frame stores its workspace too.
The class list is updated when the selected level windows changes.
Merge branch 'master' into bf-workspace
Correction de l'affichage de l'arbre des classes.
Correction de l'affichage des classes.
Merge branch 'bf-workspace' of github.com:j-jorge/bear into bf-workspace

Conflicts:
	bear-factory/bear-editor/src/bf/class_tree_ctrl.hpp
	bear-factory/bear-editor/src/bf/code/class_tree_ctrl.cpp
L'éditeur ne plante plus quand on ferme un niveau