With the drm output now waiting for the page flip on render *and* gbm and dumb buffer displays supporting triple buffering,
we don't need the entire async page flip handling logic anymore.
In the future we could turn wait_for_page_flip() into an async fn.
Updated the version from 1.1 to 1.2
Renamed the header to "Slint Royalty-free Desktop, Mobile, and Web Applications License"
Added definition of "Mobile Application" and grant of right
Moved "Limitations" to 3rd section and "License Conditions - Attributions" to 2nd section
Added flexibility to choose between showing "MadeWithSlint" as a dialog/splash screen or on a public webpage
Moved the para on copyright notices to section under "Limitations"
This is the initial implementation based on DRM dumb buffers,
which cleans up various things at the same time:
- DRM output is separate from GBM and DRM dumb buffer displays.
The latter two re-use the former.
- The timer refresh for the Vulkan KHR Display rendering lives
now with the KHR display code, in hope to be replaced with a
better mechanism in the future.
What's missing still is support for partial updates as well as
rendering with our own software renderer.
