Bump default value for "-limiter" parameter.

[goodusername123]

This feature was added as a hack/workaround in ZHLT/VHLT version 31 for overbright not working in GoldSrc, However after the 25th Anniversary update for GoldSrc/Half-Life this is no longer needed to be at such a low value.

255 may not be the perfect value (might be better to just disable the lightmap limiter altogether?), However it is a way better value then 188 and is what ZHLT/VHLT recommended for the Trinity Renderer which doesn't suffer from overbright not working so I would say this is fine for now.

Also might be worth it to update the readme since there is likely a large amount of people who are unaware of this.