Remember last config file path when loaded from CLI too

lib/Slic3r/GUI/SkeinPanel.pm

@@ -10,7 +10,7 @@ use Wx::Event qw(EVT_BUTTON);
 use base 'Wx::Panel';
 
 my $last_dir;
-my $last_config;
+our $last_config;
 
 sub new {
     my $class = shift;

slic3r.pl

@@ -59,6 +59,8 @@ Slic3r::Config->save($opt{save}) if $opt{save};
 
 # start GUI
 if (!@ARGV && !$opt{save} && eval "require Slic3r::GUI; 1") {
+    no warnings 'once';
+    $Slic3r::GUI::SkeinPanel::last_config = $opt{load};
     Slic3r::GUI->new->MainLoop;
     exit;
 }