UPGRADE.md

Upgrading to v2

• The library is now licensed under the more permissive MIT License.
• recvEvent and recvEventTimed functions removed.
  • These functions don't make sense in the event-driven world of Node.
• Connection constructor now always takes a socket.
  • Added createInbound and createOutbound static methods instead of constructor overloads.
• Show no longer accepts a format and always uses json.