Commit Briefs
allow changing the attributes
`attr' now follows the same rule as `fg' and `bg', with the three airity variant. Attributes by themselves are a comma-separated list of keywords, each one representing a ncurses attribute.
rework color management: introduce the trailing props
now, instead of prefix and line style, I'm adding the trailing style too. This changed the configuration syntax too.
add enable-colors (variable)
currently unused, will help later when adding colour support
move all cmd_* functions in their own file
this detangles definitely the commands from the ui. Various variables and struct from ui.c needed to be exported, aside from that, no functional changes.