Issues with new auto dl

[Avygeil]

Basejka auto dl sucks, but it's the only way to download maps on such clients. By mirroring cl_allowDownload 1 we can force non openjk clients to download maps so they can join pug servers. Unfortunately, smod auto dl doesn't override it and also gets fooled by the server. It's ok if we disable it for smod users by checking for smod_ver in user info. But there are still 2 problems:

• smod_ver seems to be a recent cvar, which excludes old smod users from being detected.
• basejka checksum detection is useless. Clients with "all in one" map pk3s, or servers using "fixed" bsps will result in the map getting downloaded. Even with an engine fix, the client only sends unnamed checksums to the server, so we can't mirror them in the server response.

It's fine if we make everyone use the latest smod, but there will definitely still be inconsistencies left. Could still check the cgame checksum against every known smod checksum but, there has to be a better way i guess

[Avygeil]

teh brought up an interesting point, we can force sv_pure 1 on the client to force them to list their pk3s. Could use that as a last resort solution if we can't fully detect fastdl clients.

[Avygeil]

After some thought, an engine patch will allow the most compatibility since it's the only place where we can directly append server info without additional cvars. Everything should be fine if done well on the engine.