Add wxItemAttr::HasColours() and IsDefault() accessors

They are trivial but useful to have as testing for HasBackgroundColour() ||
HasTextColour() || HasFont() is too verbose.

include/wx/itemattr.h

@@ -39,6 +39,9 @@ public:
     bool HasBackgroundColour() const { return m_colBack.IsOk(); }
     bool HasFont() const { return m_font.IsOk(); }
 
+    bool HasColours() const { return HasTextColour() || HasBackgroundColour(); }
+    bool IsDefault() const { return !HasColours() && !HasFont(); }
+
     const wxColour& GetTextColour() const { return m_colText; }
     const wxColour& GetBackgroundColour() const { return m_colBack; }
     const wxFont& GetFont() const { return m_font; }

interface/wx/itemattr.h

@@ -17,7 +17,7 @@
 
     @see @ref overview_listctrl
 
-    @since 3.1.1 (previous versions had the identical wxListItemAttr class)
+    @since 3.1.1 (previous versions had a similar wxListItemAttr class)
 */
 class wxItemAttr
 {
@@ -55,6 +55,13 @@ public:
     */
     bool HasBackgroundColour() const;
 
+    /**
+        Returns @true if either text or background colour is set.
+
+        @see HasBackgroundColour(), HasTextColour()
+    */
+    bool HasColours() const;
+
     /**
         Returns @true if the currently set font is valid.
     */
@@ -65,6 +72,11 @@ public:
     */
     bool HasTextColour() const;
 
+    /**
+        Returns @true if this object has no custom attributes set.
+     */
+    bool IsDefault() const;
+
     /**
         Sets a new background color.
     */