Refactor build scripts.
Update paths to MoltenVKGLSLToSPIRVConverter framework in demos.
Fix rare build race condition on MoltenVKShaderConverter link to MoltenVK.
The fetchDependencies script puts build files in External/build directory.
Xcode puts build files in standard Library/.../DerivedData directory.
Copy compiled external static library files to External/build/iOS &
External/build/macOS regardless of location of intermediates.
Support creation of static library and build framework and dynamic library from it.
Add Makefile to better support command line or script building integration.
Update demos to each use one of framework, static library, and dynamic library.
Refactor and rename the build scripts.
Refactor and rename the Xcode Schemes.
Update build and runtime documentation.
Update What's New document.
