Fix test_events on Python older than 3.5
Fix test_events on Python older than 3.5

Skip SSL tests on the ProactorEventLoop if ssl.MemoryIO is missing

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