1.6.0 release

Merge pull request #50 from albanobattistella/patch-4

Update it.po

Release info

Merge pull request #43 from matfantinel/flatpak-translations

Flatpak translations

Update patch and manifest

Add elementary-theme patch to manifest

Add LMDB as submodule in flatpak manifest

Update flatpak manifest and appdata

Update version number

Updated screenshots