STALKER: Clear Sky Tweak Guide

Since STALKER: Clear Sky is not dramatically different to the original STALKER in many respects, much of the customization and tweaking advice in Clear Sky is the same as that in Shadow of Chernobyl. However because there are two entirely new rendering modes, a whole range of additional settings and new tweaks, as well as tweaks which no longer work in Clear Sky, I've written this STALKER: Clear Sky Tweak Guide to allow users to fully understand and customize Clear Sky thoroughly to better meet their needs.