add binding of config variables

[rfomin]

A system like in Chocolate Doom for config variables, so we can potentially reduce the number of global variables and achieve better "encapsulation". I also think it's more convenient to bind config variables in a module rather than in m_config.c.

Should I continue?

[fabiangreffrath]

I like this approach, but how dows it help to reduce the number of global variables?

[rfomin]

I like this approach, but how dows it help to reduce the number of global variables?

Theoretically, we could make all sound module variables static and remove them from the .h files. The same applies to the video and input variables.

[fabiangreffrath]

Ah, right!

[rfomin]

Maybe I overdid it. @fabiangreffrath What do you think?

[fabiangreffrath]

What do you mean? Well, the patch is super invasive, but we knew that before, but the implementation is as clean as it can get.

[rfomin]

Should we now let @MrAlaux review the cvar descriptions?

Yes, sure.