Updates require_var() and set_variable_if_unset() to use the
environment values for named variables.
CMake processes toolchain files multiple times, and on some
processing runs cache variables are not available. Environment
variables are always available.
-Increase version to 1.0.1
-Update Javascript decode timing example
-Fix async creation of DracoDecoderModule
-fixes wasm parallel decoding
-Introduce base class for geometric normal predictor
-Added integer attribute interface to JavaScript decoder
-Move loading Draco decoder into three.js Draco loader
-Add compiler launcher support to CMake build
-Add sanitizer support via CMake build
-Check we are not reading past the end of the attribute buffer
