Preliminary Counter Strike 2 (CS:GO Source 2) Support

This alpha release adds initial support for CS2.

go get github.com/markus-wa/demoinfocs-golang@v3.4.0-alpha.0

Expect bugs and significant changes as we figure out the details.

A lot of events aren't working yet, but events.Kill should mostly work.

Watch out for bad data, there are still a bunch of bugs.