Font links outdated

Hi, the links to download Charis Doulos Gentium are dead.

These links work:

```
<a target="_top" href="https://software.sil.org/charis/">Charis SIL</a>, 
<a target="_top" href="https://software.sil.org/doulos/">Doulos SIL</a>, or
<a target="_top" href="https://software.sil.org/Gentium">Gentium</a> Unicode fonts.
```