Updated assets

assets/images/desktop@1180.png

assets/images/desktop@363.png

assets/images/desktop@474.png

assets/images/desktop@590.png

assets/images/desktop@726.png

assets/images/desktop@948.png

assets/images/material_dark@220.png

assets/images/material_dark@266.png

assets/images/material_light@220.png

assets/images/material_light@266.png

assets/images/material_light@335.png

assets/images/material_light@352.png

assets/images/material_light@532.png

assets/images/notifications@363.png

assets/images/notifications@474.png

assets/images/notifications@590.png

assets/images/tablet@thumb.png