Fix #60

Basic policy

• Make a new crate (interledger-echo)
  • It seemed that services had its own crate like interledger-ildcp
• Define the service in server.rs file
  • It seemed that:
    • server.rs processes incoming data
    • client.rs connects to the other nodes and process its connections
• Insert the service into each connection (probably in cli.rs):
  1. BTP connections
  2. HTTP connections

memo

•