Squashed 'cmake-modules/' content from commit 29bed22

git-subtree-dir: cmake-modules
git-subtree-split: 29bed2226f33a6c2987f3e1bd309e6fdb6c8850f
Removed old CMakeModules folder
replaced ADD_MSVC_PRECOMPILED_HEADER with add_pch
added the new cmake-modules folder to the cmake modules path, included AddPch and ConditionalSources at the root level.
replaced MSVC_DISABLED_FILES with add_conditional_sources
added some usage of the conditional_sources functions