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