Added possibility for upload to Duet

Further changes:
- Added new configuration option Host Type
- Added abstract base class for future printer hosts
- Moved location of upload dialog (also made it a little bit more configureable)
- added possibility to send file via postfield instead a new frame

lib/Slic3r/GUI/Plater.pm

@@ -53,7 +53,7 @@ sub new {
     my $self = $class->SUPER::new($parent, -1, wxDefaultPosition, wxDefaultSize, wxTAB_TRAVERSAL);
     $self->{config} = Slic3r::Config::new_from_defaults_keys([qw(
         bed_shape complete_objects extruder_clearance_radius skirts skirt_distance brim_width variable_layer_height
-        serial_port serial_speed octoprint_host octoprint_apikey octoprint_cafile
+        serial_port serial_speed host_type print_host printhost_apikey printhost_cafile
         nozzle_diameter single_extruder_multi_material wipe_tower wipe_tower_x wipe_tower_y wipe_tower_width
 	wipe_tower_rotation_angle extruder_colour filament_colour max_print_height printer_model
     )]);
@@ -1569,7 +1569,7 @@ sub on_export_completed {
             $message = L("File added to print queue");
             $do_print = 1;
         } elsif ($self->{send_gcode_file}) {
-            $message = L("Sending G-code file to the OctoPrint server...");
+            $message = L("Sending G-code file to the Printer Host ...");
             $send_gcode = 1;
         } else {
             $message = L("G-code file exported to ") . $self->{export_gcode_output_file};
@@ -1585,9 +1585,10 @@ sub on_export_completed {
 
     # Send $self->{send_gcode_file} to OctoPrint.
     if ($send_gcode) {
-        my $op = Slic3r::OctoPrint->new($self->{config});
-        if ($op->send_gcode($self->{send_gcode_file})) {
-            $self->statusbar->SetStatusText(L("OctoPrint upload finished."));
+        my $host = Slic3r::PrintHostFactory::get_print_host($self->{config});
+
+        if ($host->send_gcode($self->{send_gcode_file})) {
+            $self->statusbar->SetStatusText(L("Upload to host finished."));
         } else {
             $self->statusbar->SetStatusText("");
         }
@@ -1914,8 +1915,8 @@ sub on_config_change {
         } elsif ($opt_key eq 'serial_port') {
             $self->{btn_print}->Show($config->get('serial_port'));
             $self->Layout;
-        } elsif ($opt_key eq 'octoprint_host') {
-            $self->{btn_send_gcode}->Show($config->get('octoprint_host'));
+        } elsif ($opt_key eq 'print_host') {
+            $self->{btn_send_gcode}->Show($config->get('print_host'));
             $self->Layout;
         } elsif ($opt_key eq 'variable_layer_height') {
             if ($config->get('variable_layer_height') != 1) {