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
This API allows specifying a callback that will be invoked when setting
up graphics (great for compiling shaders), before rendering a frame (but
after the clearning of the surface background), after rendering a frame
(before swapbuffers) and when releasing graphics resources.