also copy payment requests when creating a reversal transaction
use sRGB colorspace instead of RGB in image conversion.

> Note, ImageMagick assumes the sRGB colorspace if the image format does not indicate otherwise.
http://www.imagemagick.org/script/command-line-options.php#colorspace
If original format is matched or format is empty string return original content of PDF document.
Adjust test accordingly and fix bad test.
Revert "use sRGB colorspace instead of RGB in image conversion."

This reverts commit a407286805ed97387fbb0afa24d8c7c059bc72b0.
=> it makes test testERP5WebWithDms failing. Please update unit
test and also add test to check what you fixed with this change.
Merge remote-tracking branch 'origin' into aurel-stock-cache