Callback function added to UIMainWindow to trigger events when the selection in the project view changes.

Performance counter activated when F12 is pressed.

Bug fixed in the SetVisible()/SetHidden() functions of UIParams that haven't created a QLabel during their initialization.

Obsolete glEnable/glDisable on texture target removed from Bind()/Unbind() of Texture class in the GPU module.

Bug fixed in the hotkey F1-12 / SHIFT+F1-12 for saving / reloading view parameters in the GLViewer in 3D mode.

SelectionManagerMeshTexels modified so that the size of the managed texture can be changed on-the-fly.

Gives the possibility to concatenate multiple source files.

# Conflicts:
#	GLViewer/GLViewer.cpp

RealTimeSelectionListener modified so as to add the possibility to update the selection z-buffer during the selection action, on mouse pressed/release/moved events, instead of just when entering the selection mode.