Add PDF writer.

test/video/TestVideoDecoder.cpp

@@ -0,0 +1,25 @@
+#include "Video.h"
+#include "Image.h"
+#include "FfmpegInterface.h"
+#include "PngWriter.h"
+#include <iostream>
+
+int main()
+{
+    auto video = Video::Create();
+    video->SetPath("/home/jmsgrogan/test.mp4");
+
+    FfmpegInterface decoder;
+    auto images = decoder.decodeToImages(video, 4);
+    std::cout << "Got " << std::to_string(images.size()) << std::endl;
+
+    PngWriter writer;
+    for(unsigned idx=0; idx<20; idx++)
+    {
+        auto filename = "test_out" + std::to_string(idx) + ".png";
+        writer.SetPath(filename);
+        writer.Write(images[idx]);
+    }
+
+    return 0;
+}