V 2.1.1.0

• automatically convert image resources between straight and premultiplied alpha (#108)
  • imported images are assumed to be straight alpha (as per PNG specification), and thus converted to premul. alpha.
  • exported images are assumed to be premultiplied alpha and thus converted to PNG standard conforming straight alpha.
  • STREAM resources (DWMxxxxxx classes) are never converted, because they already come as straight alpha.
• added a readonly edit box to the control preview (#152)