make package modern → 40% faster

Does your package still use old debhelper style? How about considering to make it modern.

I've tried to make fontforge package cleanup and use dh style since it fails with -j4 build option. And as the result, its debian/rules file become 1/3 (187→53) and it reduces build time 40% with parallel option.

• before
• real 5m13.605s
• after
• real 3m24.121s

(both cowbuilder on tmpfs)