Merge pull request #679 from MRIG/master

Updated Dutch translation
Fix #9325: Add ICC profile to exported PNGs
Read ICC profile from PNGs
Prevent resource leak in PNG ICC read code
Test commit
lua : delegate post-import events to a sub-thread

this avoids locking the UI when importing single images instead
of directories
Fix small memleak introduced in last commit
PNG: hopefully fix support for libpng-1.5+ version
Fix #10120: Don't put tags more than once into XMP

This includes some rewrites of helper functions
noise profile: sony ilce-7 by per oestlund
noise profile: canon eos 700d
gphoto: only scan for devices when explicitly requested

over the years this has caused various issues in various situations,
sometimes even allowing darktable to not start because of lack of
a USB controller for example.

gphoto should never be put in a position where it can cause trouble
for users who are not using any of it's features.
wb_presets: nikon d5200 (thanks to martin juřen)
Add tagging to darkroom

... feel free to revert if it's not cool :)
ColorIn IOP: update comment about supported formats with support for embedded color profiles