Added Powered by Fate Logos, Dice & Stress

Added 2 versions of the _**Powered by Fate**_ logos:
**poweredbyfatedark.svg** and
**poweredbyfatelight.svg** derived from
[Powered-by-Fate-Logos.zip](http://www.faterpg.com/wp-content/uploads/20
13/06/Powered-by-Fate-Logos.zip). Added the 3 Fate Dice(tm) faces
**blank.svg**, **minus.svg**, **plus.svg**; the 4 Fate Actions Icons:
**attack.svg**, **createadvantage.svg**, **defend.svg**,
**overcome.svg**; and the 2 Fate Stress Boxes **box-empy.svg**,
**box-filled.svg** derived from
[Fate-Core-Font.ttf_.zip](http://www.faterpg.com/wp-content/uploads/2013
/06/Fate-Core-Font.ttf_.zip). All used with permission as per Fate
licensing pages at
[_www.faterpg.com/licensing/_](http://www.faterpg.com/licensing/).