Add the Go API for a vertical separator

fixes andlabs/ui#315

separator.go

@@ -16,7 +16,7 @@ type Separator struct {
 	s	*C.uiSeparator
 }
 
-// NewSeparator creates a new horizontal Separator.
+// NewHorizontalSeparator creates a new horizontal Separator.
 func NewHorizontalSeparator() *Separator {
 	s := new(Separator)
 
@@ -26,6 +26,16 @@ func NewHorizontalSeparator() *Separator {
 	return s
 }
 
+// NewVerticalSeparator creates a new vertical Separator.
+func NewVerticalSeparator() *Separator {
+	s := new(Separator)
+
+	s.s = C.uiNewVerticalSeparator()
+	s.c = (*C.uiControl)(unsafe.Pointer(s.s))
+
+	return s
+}
+
 // Destroy destroys the Separator.
 func (s *Separator) Destroy() {
 	C.uiControlDestroy(s.c)

ui.h

@@ -190,6 +190,7 @@ _UI_EXTERN uiProgressBar *uiNewProgressBar(void);
 typedef struct uiSeparator uiSeparator;
 #define uiSeparator(this) ((uiSeparator *) (this))
 _UI_EXTERN uiSeparator *uiNewHorizontalSeparator(void);
+_UI_EXTERN uiSeparator *uiNewVerticalSeparator(void);
 
 typedef struct uiCombobox uiCombobox;
 #define uiCombobox(this) ((uiCombobox *) (this))