[#1642] Make GNOME GUI fresher and younger ;)

sflphone-client-gnome/pixmaps/accept.svg

sflphone-client-gnome/pixmaps/busy.svg

sflphone-client-gnome/pixmaps/hang_up.svg

sflphone-client-gnome/pixmaps/hold.svg

sflphone-client-gnome/pixmaps/icon_accept.svg

sflphone-client-gnome/pixmaps/icon_hangup.svg

sflphone-client-gnome/pixmaps/icon_hold.svg

sflphone-client-gnome/pixmaps/icon_unhold.svg

sflphone-client-gnome/pixmaps/incoming.svg

sflphone-client-gnome/pixmaps/mailbox.svg

sflphone-client-gnome/pixmaps/missed.svg

sflphone-client-gnome/pixmaps/outgoing.svg

sflphone-client-gnome/pixmaps/rec_call.svg

sflphone-client-gnome/pixmaps/refuse.svg

sflphone-client-gnome/pixmaps/transfert.svg

sflphone-client-gnome/pixmaps/unhold.svg

sflphone-client-gnome/src/menus.c

sflphone-client-gnome/src/toolbar.c