Some binding can't be express with the current data structures because
they reference propertis within inner elements within a component.
The fix is a bit involved and the best is to have an error istead of a
panic, for now.
Because of issue #1394 and because the semantic are not properly defined
currently, we decided that future version of slint should always and only
take the binding from the right hand side, even if it has no bindings.
Since we can't change the behavior in 0.2, just add a warning instead for now.
The warning can be silenced by setting a default binding for the property on the rhs.
Ignoring the warning can still lead to panic (the one in #1394)
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.
