Fixing a lot of snap issues, updating translations

- Files are now properly opened in snapcraft
- Added latex dependencies to snapcraft (tho it's buggy atm)
- Added changelog to snapcraft

linux/snapcraft/launcher/launch-logarithmplotter

@@ -10,5 +10,13 @@ set \
 # GTK theme integration (we have Qt fetch the GTK theme mirroring the host Qt theme...)
 #export QT_QPA_PLATFORMTHEME=kde
 
-# Finally run the next part of the command chain
-${@} --no-check-for-updates
+# Check if the last parameter is a file, and if so, add the argument "--no-checks-for-updates" BEFORE it.
+last="${@:$#}" # last parameter 
+length=$(($#-1))
+args=("${@:1:$length}")  # all parameters except the last
+
+if [ -f "$last" ]; then
+	${args} --no-check-for-updates "$last"
+else
+	${@} --no-check-for-updates
+fi