Original implementation of Resampling Image filters

This involves also resizing the renderbuffer of the clone source. Upsampling is cubic (faster approximation) and Downsampling is bilinear.

FrameBufferFilter.h

@@ -20,6 +20,7 @@ public:
     typedef enum {
         FILTER_PASSTHROUGH = 0,
         FILTER_DELAY,
+        FILTER_RESAMPLE,
         FILTER_BLUR,
         FILTER_SHARPEN,
         FILTER_EDGE,