GPU_SINGLE_ALLOC_PERCENT is all you need for eth mining

[nerdralph]

And that's only if you have a 2GB card.  I see lots of posts where people say you need a whole bunch of env vars set, but they obviously haven't tested each one.  I even see this in Claymore's docs, which is a bit surprising for someone who writes mining software.  The extra settings aren't necessarily harmless, as I've seen posts where people were getting low hashrates when they had set GPU_USE_SYNC_OBJECTS.