Improve filter on import

Instead of showing all images, we set the filter to the smaller of the
default import rating and the current filter. This ensures that the
imported images are shown, but that we don't reduce the filter
unnecessarily.
Update comments for improved import filter handling
Keep old import filter reset for collect operations
colisa: new module for contrast-lightness-saturation adjustment
Make it possible to translate lightness with context.

Here we are not talking about HSL lightness. Needed for French translation.
Update French translation for lowpass module.
Merge branch 'lowpass-translation'

* lowpass-translation:
  Update French translation for lowpass module.
  Make it possible to translate lightness with context.
pfm: move fallback date/time initialization to exif reading time.

this way it'll be done on import, not on thumbnail loading time.
colisa: module icons
usermanual: docs for contrast-lightness-saturation module
colisa: fix bug in process()
Fix generic fileop control job progress.
A few new strings
[l10n] Swedish update: 2 fuzzies
masks: fix bug in path rendering
Merge branch 'master' of ssh://github.com/darktable-org/darktable
Merge branch 'colisa'
blending: increase maximum permissible blur radius to 100
updated translation
Merge branch 'master' of github.com:darktable-org/darktable