Add proper support for custom client schemes, HUD layouts, etc. + related changes to HL2 Protagonist System#510

Blixibon wants to merge 4 commits intomapbase-source:developmapbase-source/source-sdk-2013:developfrom

Blixibon:mapbase/feature/custom-hud-and-protag-sys-changesBlixibon/source-sdk-2013:mapbase/feature/custom-hud-and-protag-sys-changesCopy head branch name to clipboard