Fix multiple issues in qvm-copy-to-dom0.sh

Fix multiple issues with filenames containing spaces and starting dashes.
The result is not tested by me at all, please check the changes before use.

code/productivity/qvm-copy-to-dom0.sh

@@ -6,13 +6,13 @@
 # Initial author: https://github.com/one7two99/
 
 # command line parameters
-AppVM=$1       # must be present
-Source=$2      # must be present
-Destination=$3 # optionally
+AppVM="$1"       # must be present
+Source="$2"      # must be present
+Destination="$3" # optionally
 
 # if no Destination given on commandline use ~/QubesIncoming
-if [ -z "$3" ];then mkdir -p ~/QubesIncoming && \
-                    Destination=~/QubesIncoming/$(basename $Source); fi
+if [ -z "$Destination" ];then mkdir -p -- "~/QubesIncoming" && \
+                    Destination="~/QubesIncoming/$(basename "$Source")"; fi
 
 # copy file from AppVM to dom0
-qvm-run --pass-io $AppVM "cat $Source" > $Destination
+qvm-run --pass-io $AppVM "cat -- \"$Source\"" > "$Destination"