Post release bump to 0.13.0
Post release bump to 0.13.0

pwithnall/mx,jonnylamb/mx,clutter-project/mx,pwithnall/mx,clutter-project/mx,jonnylamb/mx,clutter-project/mx,jonnylamb/mx,pwithnall/mx,pwithnall/mx,clutter-project/mx,jonnylamb/mx