Merge pull request #232 from guitorri/darktable-1.2.x

Update string freeze pt_BR
Updated pl.po for 1.2.1
Cleared two fuzzies
[l10n] Swedish update: better translation of one string.
Review and update existing Thai language translation - Backport from git master to 1.2.x stable branch.
updated translation pt_PT - string freeze darktable 1.2.1 release
Add new Thai translation backport to darktable-1.2.x
Merge pull request #235 from tawtao/thai-lang-translation-for-1.2.x

Add new Thai translation backport to darktable-1.2.x
update of dutch translations
Merge branch 'darktable-1.2.x' of https://github.com/darktable-org/darktable into darktable-1.2.x
Fix: 19 fuzzy translations, 6 untranslated messages.
Updated japanese translation by a3novy, 2 fuzzies.