[enhancement] Ability to expand

[Tintef]

Hi! First of all, great library!

I think a pretty common use case for this library is showing a brief preview of the text and let the user expand the preview to see the full text. In my case, I'm handling the expanded state on my component and either rendering the text itself of the one wrapper by the library, but it would be cool if the library supported this.

For this, I can think of two approaches:

• Adding a maxLines value on the onReflow function, so we can dynamically change between a small number and that one.
• Add a new prop to support this

What do you think? Thanks!