terminal: Try both terminfo and termcap names when running tput

FreeBSD doesn't have a terminfo database, and its tput command only
support termcap names. To make bold text works on more systems, we try
both terminfo and tercap names before giving up and using normal text.

This commit also adds terminfo 'setaf' as an alternative to 'setf'
because it seems that the latter only works with xterm, not with other
popular terminals such as xterm-256color and screen.

https://bugzilla.gnome.org/show_bug.cgi?id=774070