Revert change from 2008-05-28 that mapped words and word pairs that

Revert change from 2008-05-28 that mapped words and word pairs that
indicate weight or stretch into the corrersponding Pango font
description setting and stripped those word(s) from the family name.

Personally I liked the effect this had on the GTK+ font picker,
combining all weight and stretch variants of what de facto is one
typeface family (for instance DejaVu) under one family name. But Bulia
Byak reported that this caused regressions in Inkscape. So OK then.