Fix in JsonMessage constructor for #1384
don't us a single path for the build directory; different resources may have different mappings.
Solves #590, adds some new dubbed videos to the size list.
Updating video sizes, moving to updates app (where this is used, anyway)
solve #1381: Define settings.LANGUAGES based on language packs we have downloaded
Merge pull request #1395 from aronasorman/1381

solve #1381: Define settings.LANGUAGES based on language packs we have downloaded
fix #1381: show language's native names if possible in the installed
languages list
Merge pull request #1396 from aronasorman/1381

fix #1381: show language's native names if possible in the installed language list
Merge remote-tracking branch 'refs/remotes/upstream/develop' into develop