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

xs/xsp/Utils_OctoPrint.xsp

@@ -1,13 +0,0 @@
-%module{Slic3r::XS};
-
-%{
-#include <xsinit.h>
-#include "slic3r/Utils/OctoPrint.hpp"
-%}
-
-%name{Slic3r::OctoPrint} class OctoPrint {
-    OctoPrint(DynamicPrintConfig *config);
-    ~OctoPrint();
-
-    bool send_gcode(std::string filename) const;
-};

xs/xsp/Utils_PrintHost.xsp

@@ -0,0 +1,10 @@
+%module{Slic3r::XS};
+
+%{
+#include <xsinit.h>
+#include "slic3r/Utils/PrintHost.hpp"
+%}
+
+%name{Slic3r::PrintHost} class PrintHost {
+	bool send_gcode(std::string filename) const;
+};

xs/xsp/Utils_PrintHostFactory.xsp

@@ -0,0 +1,13 @@
+%module{Slic3r::XS};
+
+%{
+#include <xsinit.h>
+#include "slic3r/Utils/PrintHostFactory.hpp"
+%}
+
+%name{Slic3r::PrintHostFactory} class PrintHostFactory {
+    PrintHostFactory();
+    ~PrintHostFactory();
+
+   static PrintHost * get_print_host(DynamicPrintConfig *config);
+};

xs/xsp/my.map

@@ -239,9 +239,11 @@ Ref<TabIface> 				O_OBJECT_SLIC3R_T
 PresetUpdater*              O_OBJECT_SLIC3R
 Ref<PresetUpdater>          O_OBJECT_SLIC3R_T
 
-OctoPrint*                  O_OBJECT_SLIC3R
-Ref<OctoPrint>              O_OBJECT_SLIC3R_T
-Clone<OctoPrint>            O_OBJECT_SLIC3R_T
+PrintHostFactory*            O_OBJECT_SLIC3R
+Ref<PrintHostFactory>        O_OBJECT_SLIC3R_T
+Clone<PrintHostFactory>      O_OBJECT_SLIC3R_T
+
+PrintHost*                   O_OBJECT_SLIC3R
 
 Axis                  T_UV
 ExtrusionLoopRole     T_UV

xs/xsp/typemap.xspt

@@ -270,3 +270,4 @@
 };
 %typemap{AppController*};
 %typemap{PrintController*};
+%typemap{PrintHost*};