add a personal wordpress blog to share options

this commit introduces an option to add a personal wordpress blog to the sharing buttons, that uses the [press-this.php](http://codex.wordpress.org/Press_This) function of wordpress. you can configure your personal wordpress url via an entry in ``config.ini`` like this: 

        wordpress=https://mcnesium.com

the short code for ``share=`` obviously is a **w** :-)