This also separates the blend-to-screen part of render_layer into a
helper function, as that will be useful in the future with public layer
elements.
Relates to #725
Delegate the decision how to implement the Clip element entirely into the backend,
where the GL backend can now explicitly render
children into a layer, instead of the hack with a layer in the renderer's
state and the extra save/restore pair.
The render function now takes a self_rc and returns a enum that permits
the implementation to handle rendering of children on its own and
thus make the caller skip that traversal step.
The README.md contains the warning that used to be in lib.rs.
Add README.md files to all internal crates
... pointing to the official public crate to use instead.
Rename internal crates
fixup: README files
fixup rename
Move "internal" crates into the `internal` directory. This first batch
includes most of sixtyfps_runtime but leaves the rendering backends
alone for now.
pre-commit applied some cleanups to the moved files:
- Consistent newline at end of file policy
- trimming trailing whitespace
- Formatting Cargo.toml files.
