Added TabIface C++ wrapper for GUI::Tab C++ class,

exported the TabIface to Perl.

xs/xsp/GUI.xsp

@@ -37,3 +37,6 @@ void add_debug_menu(SV *ui)
 
 void create_preset_tabs(PresetBundle *preset_bundle, AppConfig *app_config, int event_value_change, int event_presets_changed)
     %code%{ Slic3r::GUI::create_preset_tabs(preset_bundle, app_config, event_value_change, event_presets_changed); %};
+
+Ref<TabIface> get_preset_tab(char *name)
+    %code%{ RETVAL=Slic3r::GUI::get_preset_tab_iface(name); %};

xs/xsp/my.map

@@ -229,6 +229,8 @@ PresetBundle*	    		O_OBJECT_SLIC3R
 Ref<PresetBundle>    		O_OBJECT_SLIC3R_T
 PresetHints*	    		O_OBJECT_SLIC3R
 Ref<PresetHints>    		O_OBJECT_SLIC3R_T
+TabIface*	   				O_OBJECT_SLIC3R
+Ref<TabIface> 				O_OBJECT_SLIC3R_T
 
 Axis                  T_UV
 ExtrusionLoopRole     T_UV

xs/xsp/typemap.xspt

@@ -207,6 +207,8 @@
 %typemap{Ref<PresetBundle>}{simple};
 %typemap{PresetHints*};
 %typemap{Ref<PresetHints>}{simple};
+%typemap{TabIface*};
+%typemap{Ref<TabIface>}{simple};
 
 %typemap{PrintRegionPtrs*};
 %typemap{PrintObjectPtrs*};