events: Use __slots__ in Handle and TimerHandle
events: Use __slots__ in Handle and TimerHandle

haypo/trollius,gvanrossum/asyncio,ajdavis/asyncio,ajdavis/asyncio,1st1/asyncio,vxgmichel/asyncio,haypo/trollius,jashandeep-sohi/asyncio,fallen/asyncio,vxgmichel/asyncio,manipopopo/asyncio,gvanrossum/asyncio,manipopopo/asyncio,gsb-eng/asyncio,1st1/asyncio,fallen/asyncio,jashandeep-sohi/asyncio,Martiusweb/asyncio,gsb-eng/asyncio,gsb-eng/asyncio,jashandeep-sohi/asyncio,ajdavis/asyncio,gvanrossum/asyncio,Martiusweb/asyncio,vxgmichel/asyncio,1st1/asyncio,manipopopo/asyncio,fallen/asyncio,haypo/trollius,Martiusweb/asyncio