restrict cursor to 16:9 area to prevent ultra-wide fov cheat

[Victor-Diego]

also added two new convars:
rd_draw_restricted_borders (def="1") -> Display the restricted cursor area when using ultra-wide resolution
rd_draw_restricted_borders_color (def="128 128 128 128") -> Color of the restricted cursor area borders

[Victor-Diego]

For testers:
Alien Swarm Reactive Drop\reactivedrop\cfg\video.txt <- Modify the file to customize game resolution
Borders should be displayed only when using resolution wider than 16:9

[BenLubar]

For testers: Alien Swarm Reactive Drop\reactivedrop\cfg\video.txt <- Modify the file to customize game resolution Borders should be displayed only when using resolution wider than 16:9

You can also start AS:RD with -w 1920 -h 540 on the command line for 32:9