support netbsd-curses terminfo format

[mauke]

Look into supporting other terminfo formats than ncurses, such as netbsd-curses.

Related: https://github.com/sabotage-linux/netbsd-curses/

[krytarowski]

NetBSD curses uses cdb(5) - constant database format in 1 file.

[rofl0r]

i don't know a lot about unibilium, but maybe it would be possible to add a mode that just uses (n)curses behind the scenes ? that would make it compatible with all sorts of existing terminfo db implementations existing (freebsd, netbsd) and future. feel free to slap me with a large trout if that is impossible or a crazy idea. ;)