Currently the Qt backend still redirect everything to the GL backend,
but the goal is to use QPainter and QWindow
This also adds a "default" backend, whose goal is to select the proper
backend at compile time
- Give all the sixtyfps-* create a 0.0.1 version
- Make sure that the internal dependences are using the exact same version
(so "=0.0.1")
- Add the description/homepage/repository fields in the .toml files
- Set publish=false to crates that are not meant to be published on crates.io