Make it easier to know which version of the gamelogic is running

[Kangz]

It is difficult to know which version of the gamelogic you are running and it often leads to bugs which are difficult to understand for users (and devs too, I had EU run under 0.29 instead of 0.30 for a week). Some small improvements would make that problem go away:

• Have a ROM cvar in both gamelogics with the latest git tag's name and one with the git commit hash.
• Send the content of these cvars at the gamelogic registration to be printed to the console.
• Have the server latest tag cvar sent as serverinfo to be displayed on the server list.

Then users and server operators won't be able to miss version problems.

• Mentor: Kangz
• Knowledge: Some UI, VM stuff, Cvars
• Difficulty: 4

Mentored projects on the Unv wiki

[DolceTriade]

ds already does this in his webbased browser. Perhaps we can borrow his technique.

[guillaume-uH57J9]

This would be useful. Detecting server versions would help avoid issues like #442

[Viech]

A few notes on this:

• We have to consider four versions: Client, server, client gamelogic, server gamelogic. Both server and its gamelogic's version need to be displayed in the server browser some way (one could be displayed in a column, both would be displayed on mouse-over).
• If a base version (e.g. 0.36) doesn't match, users should be prevented from connecting except if they set a certain cvar (cf. connecting to servers that load pk3dir).

@Kangz are you still working on this?

[Amanieu]

We have several mechanisms to deal with API versions, all of which we are not making use of...

GAME_API_VERSION CGAME_IMPORT_API_VERSION PROTOCOL