rawdenoise: better user experience for preview image when blending
rawdenoise: apply gaussian blur to preview buffer for a closer visual match
OSX HiDPI: fix most places, central DR view is still broken
OSX HiDPI: revert changes to map.c from last commit

since osmgpsmap will draw pixelated map anyway
OSX HiDPI: fix logo in bg of zonesystem
OSX HiDPI: fix slideshow view
OSX HiDPI: return correct mipmap level for HiDPI screens
OSX HiDPI: fix central DR view
OSX HiDPI: update package building instructions
OSX HiDPI: add config option and disable for old cairo
Updated Russian translation (97% done, good to go)
Merge pull request #778 from parafin/macosx

Retina support
colormatrices: nikon d600 enhanced matrix

thanks to Michael Below
updated about dialog to reflect contributors 1.4..1.6
release notes: update somewhat.
release: remove <95% translations. put back after release.
about: remove (partly outdated) special roles.
release notes: empty after release
Revert "release: remove <95% translations. put back after release."

This reverts commit fe7c121054c35e40091f95f9e7e606e25753c979.
Exposure IOP: deflicker is back and kicking

This reverts 461777143735bcb8698bb8487cf6a1dcd71986fa, 148e0f90172c6650e40b2ace1ce918b7b5317458