Add MVKConfiguration::fullTextureSwizzle and corresponding MVK_CONFIG_FULL_TEXTURE_SWIZZLE
env var & build setting, and set to false, to disable texture swizzling by default.
Add SPIRVToMSLConverterOptions::shouldSwizzleTextureSamples.
Lazily init queue families to allow time for specializedQueueFamilies config change.
Fix consistency of pipeline encoding state auxiliary buffer binding.
Improve documentation of MVKConfiguration environment variables and build settings.