Fix path to qrTransfer at nautilus script

    The nautilus context menu script had an old path to qrTransfer
that was replaced at some point. Also adds a download link in
README.md.

README.md

@@ -27,6 +27,8 @@ This depends most on your local network. If you're in a network that you trust (
 
 First of all, there is a lot of room for improvements here and I plan to create a graphical installer in a time to come, but for now please continue with these simple versions.
 
+Download qrTransfer [here](https://github.com/WesleyMPG/qrTransfer/releases).
+
 ###  Windows
 
 - Download the corresponding release;

src/scripts/linux/gnome/qrTransfer_nautilus.sh

@@ -9,6 +9,6 @@ then
     notify-send "No file privided"
 else
     notify-send "Uploading file ${paths[0]}"
-    ~/.local/bin/qrTransfer -p "${paths[0]}"
+    "/usr/local/bin/qrTransfer" -p "${paths[0]}"
 fi