2.15.0

1. Ability to add and remove I2P tunnels without restart
2. Strip-out Accept-* headers in HTTP proxy
3. Handle lines with comments in hosts.txt file for address book
4. Ability to disable SOCKS outproxy option
5. QT GUI
6. Don't run peer test if nat=false
7. Run router with empty netdb for testnet
8. Skip expired introducers by iexp
9. Separate output of NTCP and SSU sessions in Transports tab