Add interface + stub for width setter
Add interface + stub for height setter
Add interface + stub for width+height setter
Add implementationfor ws_abstacrt_shell_surface_set_width_and_height()
Add command for setting width of abstract shell surface
Add command for setting height of abstract shell surface
Add command for setting width and height of abstract shell surface
Add width/height members in ws_surface
Add implementation for ws_abstract_shell_surface_set_height()
Add implementation for ws_abstract_shell_surface_set_width()
Merge pull request #462 from matthiasbeyer/add-width_height_setter_for_shell_surface

Add width/height setter methods for ws_shell_surface