[PATCH] add test0 to create a simple empty window
add test1-2 to create a window with canvas inside a main window
[PATCH]: the application has to request the key signal to the widget
[PATCH]: align th pilot_wtk and pilot_theme
[PATCH]: busy defined as mutex and use function to change its value
[BUGFIX]: error in the variable targets_SOURCE
[PATCH]: pilot_widget contains a pointer of the main window that contains it
[BUGFIX]: wayland platform function moved
[BUGFIX]: wayland platform function moved
[PATCH]: pilot_theme allows to create an empty window with background color