fixed copy-paste losing formatting on Windows
was caused by wxWidgets fixing a bug that I had a workaround for :)
Update document.h

remove erroneous testing code
Fixed PNG that doesn't open in treesheets and with IDAT error in GIMP
Merge pull request #21 from prurigro/pngfix

Fixed PNG that doesn't open in treesheets and with IDAT error in GIMP
Merge pull request #2 from aardappel/master

Opdatering 08 September 2014