Update strings.xml

Translation error (ES): L856 "inificada" --> "unificada"
Update strings.xml

Danish translation added. New to Github so hopefully I did the right thing :)
Spelling mistakes

bezittelijk voornaamwoord en d/t-fout voltooid deelwoord 'verversen'
Add missing translations

colorizing missing contacts, visible refile actions, attachment dialog
Merge pull request #433 from raboof/patch-1

Dutch translation update.
Consistent Dutch translation for 'attachment'
Merge pull request #435 from raboof/patch-2

Consistent Dutch translation for 'attachment'
Merge pull request #431 from miplopez/patch-1

Update es strings.xml
Merge pull request #432 from Mittaa/patch-1

Update da strings.xml
Fix typo
Merge remote-tracking branch 'upstream/master'