Version bump to 0.4.0
Version bump to 0.4.0

samchen2009/impressionist,firmanm/impressionist,samchen2009/impressionist,guodongme/impressionist,charlotte-ruby/impressionist,charlotte-ruby/impressionist,firmanm/impressionist,samchen2009/impressionist,charlotte-ruby/impressionist,guodongme/impressionist,firmanm/impressionist,guodongme/impressionist