[ADD] WColor enhancement: Some default colors as static members added.

src/common/WColor.cpp

@@ -223,3 +223,7 @@ bool WColor::operator!=( const WColor &rhs ) const
 {
     return !( *this == rhs );
 }
+
+const WColor WColor::green( 0.0, 1.0, 0.0, 1.0 );
+const WColor WColor::red( 1.0, 0.0, 0.0, 1.0 );
+const WColor WColor::blue( 0.0, 0.0, 1.0, 1.0 );

src/common/WColor.h

@@ -128,6 +128,10 @@ public:
      */
     bool operator!=( const WColor &rhs ) const;
 
+    static const WColor green; //!< Default for green
+    static const WColor red; //!< Default for red
+    static const WColor blue; //!< Default for blue
+
 protected:
 private:
     float m_red; //!< Red channel