Steam SDK support for BlitzMax NG

Brucey dcec22d04e Merge pull request #7 from bmx-ng/task/add-ugc-setlistener		hai 5 meses
steamsdk.mod	ace3396b62 Added UGC SetListener method.	hai 5 meses
.gitignore	3a29d91a99 Update to steamworks sdk 1.53a.	%!s(int64=3) %!d(string=hai) anos
README.md	9dbff1f548 Initial commit	%!s(int64=6) %!d(string=hai) anos

steam.mod

réplica de https://github.com/bmx-ng/steam.mod.git

Steam SDK support for BlitzMax NG