Apply singlecolorpatch.diff from Amir Ebrahimi.

Add single color compressor to CUDA implementation.

src/nvimage/ColorBlock.cpp

@@ -110,6 +110,19 @@ void ColorBlock::splatY()
 	}
 }
 
+/// Returns true if the block has a single color.
+bool ColorBlock::isSingleColor() const
+{
+	for(int i = 1; i < 16; i++)
+	{
+		if (m_color[0] != m_color[i])
+		{
+			return false;
+		}
+	}
+	
+	return true;
+}
 
 /// Count number of unique colors in this color block.
 uint ColorBlock::countUniqueColors() const

src/nvimage/ColorBlock.h

@@ -24,6 +24,7 @@ namespace nv
 		void splatX();
 		void splatY();
 		
+		bool isSingleColor() const;
 		uint countUniqueColors() const;
 		Color32 averageColor() const;
 		bool hasAlpha() const;