Add separate ExternalDependencies Xcode project.
Move external dependencies to ExternalDependencies project.
The fetchDependencies script builds external dependencies libraries into External/build.
The fetchDependencies script prepares SPIRV-Tools without preparing glslang.
MoltenVK links to pre-built external dependency static libraries.
MoltenVK includes external library headers using full relative paths.
MVKCmdClearAttachments support clearing multiple attachment layers.
MVKCmdClearImage use renderpass clear, and support clearning multiple image layers.
Rename mvkCmdClearImage() to mvkCmdClearColorImage().
MVKDevice add getFormatIsSupported() to allow devices to test for format support.
MVKFramebuffer support multiple layers.
mvk_datatypes.h support both 2D and 3D mipmap calculations and allow
mvkMTLPrimitiveTopologyClassFromVkPrimitiveTopology() in iOS.
Remove support for VK_FORMAT_B10G11R11_UFLOAT_PACK32 & VK_FORMAT_E5B9G9R9_UFLOAT_PACK32
since format components are reversed on Metal.
Move OS extension source files to new OS directory.
Update to latest SPIRV-Cross version.
Update MoltenVK version to 1.0.16.
Remove duplicate build of SPIRV-Tools in fetchDependencies.
Remove folder symlinks from Externals and MoltenVKShaderCompiler folders.
Update header search paths to reference External folders directly.
Update External/README.md documentation.
Update MoltenVK version to 1.0.1 to reflect new build instructions.
Minor update to performance logging.
Load external library versions using script instead of Git submodules.
SPIRV-Cross, Vulkan-LoaderAndValidationLayers & VulkanSamples versions recorded in files.
glslang version determined by Vulkan-LoaderAndValidationLayers.
SPIRV-Tools & SPIRV-Headers versions loaded by glslang.
When MoltenVK is built as part of the LunarG SDK, use external libraries
sourced from parent Vulkan-LoaderAndValidationLayers.
Use Vulkan headers from Vulkan-LoaderAndValidationLayers.
No longer generate Vulkan specification.
Update documentation.
