- Add MVK_USE_METAL_PRIVATE_API build setting to allow MoltenVK
to be built with access to Metal private API calls.
- Add support for VkPhysicalDeviceFeatures::wideLines feature
when MVK_USE_METAL_PRIVATE_API is enabled in a MoltenVK build.
- Set lineWidthRange and lineWidthGranularity to reasonable arbitrary values.