General algorithm for Player#lookup
Use numbers for missing parts in meanings
New Meaning.has? predicate
Smarter Meaning.to_s
Add some assumptions to README
Add shortcut Grammar::Item.full?/partial?
Grammar#lookup return array
Meaning#missing_parts hash key is index
Bring back Player#learn (naive for now)
Cleaner info log
Calculate meanings_count accurately
Player#to_s gives meanings count too
Add missing Grammar::Item#embed!