* Sleeping updates the loop's current time always.

That had been disabled for libuv, but now that we run timers in our own code that's not a concern anymore.

Fixes #1227.

* Try Python 3.5.5 because of the weird Illegal Instruction crash we suddenly see with 3.5.4

* Increase the value; test_sendall_timeout was often failing to actually timeout.

* Really python3.5