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
Set description in Picasa export only if it is defined

Otherwise Picasa displays filenames as photo descriptions, which is not nice in exported albums
Use Google's terminology in variable names - title/summary, instead of caption/description

Title is the filename and summary is something that is displayed along with the photo on the web (xmp title).
Danish translation: Better translation for lossy/lossless
Merge remote-tracking branch 'upstream/master'
Danish translation: Better translations of some strings
Fix #9665: Allow toggling filmstrip in map view

Maybe we should move that code to lib/tools/filmstrip.c?
Merge pull request #315 from angryziber/master

Improve Picasa export: do not set irrelevant summary for photos consisting of a filename, keep it empty if xmp title is not defined instead
allow longer string length for camera maker/model and lens name

affects cached image data and lens correction module. should fix #9644.
focus: clip focus regions to cropped image.
focus: slight performance fix.
focus: don't display stale old clusters
Fix some strings marked for translation

YEAH! Finally I found time to fix some bogus strings before string
freeze. :)
[l10n]: Update of German translation
Update French translation.
Merge remote-tracking branch 'upstream/master'
Updated Danish translation
Merge pull request #341 from pryds/master

Updated Danish translation