0.4.1

• expose methods so one can actually create RelayInfo/RelayAgentInformation
• methods to get the data out of various Unknown variants for opts/relay
• added option 118 subnet selection
• return impl Iterator for relay/opt iterator methods
• more docs for opts/relay info

Several of these changes are breaking, including enum variant additions & changing return types of methods. The API may continue to break up until 1.0