Cleanup, add scanline mask builder

PortabilityLayer/ScanlineMaskBuilder.h

@@ -0,0 +1,25 @@
+#pragma once
+
+#include <stdint.h>
+
+namespace PortabilityLayer
+{
+	class ScanlineMaskBuilder
+	{
+	public:
+		ScanlineMaskBuilder();
+		~ScanlineMaskBuilder();
+
+		bool AppendSpan(size_t span);
+
+		size_t GetLongestSpan() const;
+		const size_t *GetSpans() const;
+		size_t GetNumSpans() const;
+
+	private:
+		size_t *m_spans;
+		size_t m_numSpans;
+		size_t m_capacity;
+		size_t m_longestSpan;
+	};
+}