Synchronised with 0.18.0

Check the connection close and new features that might be cool

The first full release

This version supports raw TCP, UDP and QUIC connections as well as HTTP, HTTPS and HTTP3.
Latest lucas-clemente quic-go and therefore NO spin bit :(

TODO: control DSCP for HTTPx (hence not yet 1.0)

Add HTTPS support

Added an HTTPS server and client using the same TLSConfig as the QUIC server/client

Add HTTP support

Start adding 'near application' behaviour.
Includes an HTTP server/client based on golang examples.
Client asks for a specific bunch of data. Server produces a string of random characters

Initial SPINBIT support

Added GOLANG modules support to control the version of the quic-go fork we need to use to get the spin bit running.

Update to the draft24 lucas-clemente quic-go release

This version adapts the code to the latest developments in the quic-go code.
Needs go 1.13

JSON support for measurement output

This version prints session level measurements as JSON strings