Fix lack of HTML encoding for stylesheet link
Fix lack of HTML encoding for stylesheet link

Previous to the fix, the home page had a line like (notice the wrongly
encoded `&`):

```html
<link rel="stylesheet" href="view/theme/frio/style.pcss?f=&puid=1"
type="text/css" media="screen" />
```

annando/friendica,tobiasd/friendica,friendica/friendica,tobiasd/friendica,fabrixxm/friendica,fabrixxm/friendica,annando/friendica,fabrixxm/friendica,tobiasd/friendica,annando/friendica,friendica/friendica,fabrixxm/friendica,tobiasd/friendica,friendica/friendica,annando/friendica,tobiasd/friendica,annando/friendica,fabrixxm/friendica,friendica/friendica,friendica/friendica