simplify observer getter/setter handling
simplify observer getter/setter handling

karevn/vue,lepture/vue,th0r/vue,karevn/vue,lepture/vue,Endika/vue,shupan123/vue-fixed-type,diermengdierme/vue,galenyuan/vue,karevn/vue,Endika/vue,shupan123/vue-fixed-type,seedalpha/vue,Endika/vue,shupan123/vue-fixed-type,th0r/vue,seedalpha/vue,diermengdierme/vue,th0r/vue,lepture/vue,galenyuan/vue,fergaldoyle/vue,galenyuan/vue,fergaldoyle/vue,fergaldoyle/vue,seedalpha/vue,diermengdierme/vue