Added text option for number-display

This will allow users to set the text attached with a number-display. (TO DO) Pluralization of text, (https://github.com/blakeembrey/pluralize) can be helpful.
Again, this doesn't allow setting multiple html's at once. IMO, the setters should just add messages to the hash, and set to undefined can be used if removing a message is needed.

With no arguments, the function should return the whole messages object.

The choosing of which to use should happen at format time.