[BUG] please expand terminfo

[slawo]

As an urxvt terminal user I'd welcome rxvt-unicode and rxvt-unicode-256color in /usr/share/terminfo/r/ Dropping the file in from another machine makes the unknown terminal errors go away. I'm not familiar enough with the topic to know if this can cause other problems.

EDIT: I encountered this in the latest rpi 3 image.