fix black background in tabs with basic Windows theme
adds hotkeys for switching to
	left   view (default ALT+LEFT)
	right  view (default ALT+RIGHT)
	top    view (default ALT+TOP)
	bottom view (default ALT+BOTTOM)
enlarge the text zone for command in hotkeys settings
cosmetic :
buttons spacing in tabs settings
better help and about icons
about dialog is easier to read