Removed timeouts in interfaces in favor of Future::after.

Review: https://reviews.apache.org/r/19672
Used Future::after in Network.

Review: https://reviews.apache.org/r/19674
Cleaned up master detector usage in tests.

Review: https://reviews.apache.org/r/19834
Refactored State::names to return a set instead of vector.

Review: https://reviews.apache.org/r/19835
Added log implementation for state storage.

Review: https://reviews.apache.org/r/19007