Merge changes Ifb3cea05,If093f4c0,If9c22b38,Idda56439,Ib3ceb46f, ...
* changes:
vulkan: Set up VkCmdBuffer dispatching
vknulldrv: Implement creation of no-op object types
vknulldrv: implement VkDeviceMemory objects
vknulldrv: implement VkBuffer objects
vulkan: add memory property queries to nulldrv and vkinfo
vulkan: initial loader and null driver
vulkan: apply 138.0..v138.2 changes to api file
vulkan: import api from upstream
vulkan: several updates to implementor's guide
vulkan: add initial vkandroid doc