Expose React Native <Text/> props to highlighted words

[Cederman]

Hi!
Thanks for an awesome package. However, it would be even more awesome if the option to pass down the text props that should be applied to the text wrapper. One issue we have now is that the allowFontScaling prop never takes effect on the highlighted word (props are only passed down to the parent Text wrapper. Maybe another prop on the component called "highLightProps" or similar can be introduced?

Reference: https://facebook.github.io/react-native/docs/text.html#allowfontscaling

[clauderic]

I'd be happy to accept a PR for this