Abbility to format title and meta description with smartypants

[mayfinn]

Kirby has the ability to format markdown text typographically correctly with smartypants (Kirby Doku). These include correct spacing, convertion from -- to – etc.

It should be possible to format Meta-Descriptions and Title via the smartypants configuration. It should automatically added when the Kirby option is set or could be overwritten via a own plugin option.

Not that text that is formatted via smartypants should run through html_entity_decode() so that the html_entities are not printed.