Allow users of the allocator to hint memory usage for downloads. This
removes the non-descriptive boolean passed for "host visible" or not
host visible memory commits, and uses an enum to hint device local,
upload and download usages.
For listing the available physical devices we can use Vulkan 1.0.
Now that MoltenVK supports 1.1 we can require it for running games.
Add missing documentation.
Report device enumeration errors with exceptions to be consistent with
other initialization related function calls. Reduces the amount of code
to maintain.
Move surface initialization code to a separate file. It's unlikely to
use this code outside of Vulkan, but keeping platform-specific code
(Win32, Xlib, Wayland) in its own translation unit keeps things cleaner.
Initialize debug callbacks (messenger) from a separate file. This allows
sharing code with different backends.
Change our Vulkan error handling to use exceptions instead of error
codes, simplifying the initialization process.
