Text attributes have been rewritten as bit flags, so for example instead of
"BoldUnderline" you'd have to define "Bold | Underline" in your theme
settings.
Requested in #21
Merge ui crate with root crate.
In preparation for uploading `meli` as a separate crate on crates.io.
Workspace crates will need to be published as well and having a separate
`ui` crate and binary perhaps doesn't make sense anymore.