Implement offline mode. Closes #1241
Merge pull request #1364 from pejakm/wof

Implement offline mode. Closes #1241
[Build] Try to use only "lrelease" binary from PATH with Qt5

If the lrelease binary is not in QT_INSTALL_BINS/lrelease, try to use
just lrelease from PATH with Qt5, instead of incorrectly trying to use
lrelease-qt4