Updated to recalculate timeout at Python level.  The current module already works this way on recv() calls. See attached.

I'd be happy to churn through and fix the other modules (using the 3.5 work as a guide), though I think only addressing the higher level abstractions makes sense (I think that's been noted elsewhere). For example, the _fileobject wrappers, but not the recv from sock_recv_guts.