add_empty_word(): Ignore stems for now
add_empty_word(): Ignore stems for now

This decreases a little the overhead for stem-suffix languages.

opencog/link-grammar,ampli/link-grammar,MadBomber/link-grammar,opencog/link-grammar,linas/link-grammar,ampli/link-grammar,linas/link-grammar,ampli/link-grammar,linas/link-grammar,opencog/link-grammar,linas/link-grammar,MadBomber/link-grammar,opencog/link-grammar,opencog/link-grammar,opencog/link-grammar,linas/link-grammar,MadBomber/link-grammar,MadBomber/link-grammar,linas/link-grammar,MadBomber/link-grammar,MadBomber/link-grammar,MadBomber/link-grammar,ampli/link-grammar,ampli/link-grammar,opencog/link-grammar,opencog/link-grammar,linas/link-grammar,ampli/link-grammar,linas/link-grammar,opencog/link-grammar,ampli/link-grammar,linas/link-grammar,ampli/link-grammar,ampli/link-grammar,MadBomber/link-grammar