building thumnails on creation of LayerDialog
building thumnails on creation of LayerDialog II
Every Layer is treated seperately
Every Layer is treated seperately switch + add + delete + change
Merge branch 'gsoc_layers_thumbnails' into gsoc_layers_list_of_command_list
working version on 1 layer
working version on 1 layer
working version on seperate layers
working version on seperate layers with history
final move in Drawing suface + cleaning up
final move in getNextCommand for Hiding+Switching
final move in getNextCommand for  Deletion + Cleaning up
thumbnails
pipette on all layelayers
flip command
flip and fill tests