Added support for href decorators

[marek-nogiec]

Hi, I needed the possibility to decorate the href in resulting links so I added it in a very simple way (hrefDecorator function passed as prop). Don't know how many people will need this but might be useful for things like link forwarding, changing domains etc.
I'm using it to pass user-generated links through a simple forwarding service which validates them and takes care of window.opener exploit.

[tasti]

Support for href decorators will be available in v1.0.0. For example:

const hrefDecorator = (href) => ...;

<Linkify hrefDecorator={hrefDecorator}>
  ...
</Linkify>

Any feedback is appreciated.