Feature request: Better HLSL Support

[Zoro-6191]

Hi, I do some HLSL stuff, and it already has so much potential, it'll be so cool to have a few more things like:
(most of these are supported in https://github.com/xoxor4d/iw3xo-dev )

• Mouse coords shader constant
• Time variable for main menu (there is no variable for time except gameTime.w which uses microsecond count since server started, thus only works in online/offline servers and not in main, connect and error menus)
• Custom shader code-constants that are linked to dvars specifically created for that matter (eg. r_hlsl_customvar1 or something) (heard bo1 has support for that)
• Maybe some GSC support for HLSL
• Servers running an extended amount of time have messed up shaders, also messed up default texture scrolling

I'm sure whole cod4x community will appreciate such a change, specially server owners and modders.

[Rex109]

Definitely a must have for modders, huge thumbs up for me!