Updated core and samples 

Renamed USAGE_STATIC to USAGE_IMMUTABLE (API240077) 

Renamed static samplers to immutable samplers (API240076) 

PSO creation refactoring (API240075) 

Updated submodules (API240073) 

Updated samples module (minor fix for UWP) 

Enabled mesh shaders (API 240068) 

Updated core & samples (added duration query, API240067) 

Another minor update to readme 

Updated tools