Consider adding extension dependencies, required version, etc

[tangmi]

Hi, would ash consider adding extension metadata to the generated output? In addition to name, I'm referring to the following fields in vk.xml's <extension> tag:

• requiresCore: the API version the extension requires
• promotedto: the API version in which this extension was promoted to core
• obsoletedby: the extension that this extension is obsoleted by
• deprecatedby: the extension that this extension is deprecated by
• requires: a list of extensions this depends on
• type: whether the extension is a "device" or "instance" extension

This would make it much simpler to write device creation code that is parameterized on a dynamic list of required features/extensions.

Here's an example of VK_KHR_get_physical_device_properties2 from vk.xml:

<extension
    name="VK_KHR_get_physical_device_properties2"
    number="60"
    type="instance"
    author="KHR"
    contact="Jeff Bolz @jeffbolznv"
    supported="vulkan"
    promotedto="VK_VERSION_1_1">

Many thanks for your time!