limit latest version support to gnome 50

Merge pull request #48 from chrisjonesBSU/add-gnome49

Add version 49 to metadata json

Merge pull request #42 from dodog/master

Added Slovak language

Merge pull request #44 from fiftydinar/patch-1

Gnome 48 support

add 400% and 500% per request #40[1;5D

gnome 47

gnome 46

migrate preference screen to libadwaita (getPreferencesWidget => fill…

…PreferencesWindow)

last version to support gnome <= 44

dash2dock compatibility issue: increase hacky delay 50 => 500ms