Enable dual buffer rd search and encoding scheme

This commit enables the dual buffer rate-distortion optimization
and encoding scheme. It stacks the original transform coefficients,
quantized levels, and reconstructed coefficients, in the rate-
distortion optimization search process, hence eliminates the need
to re-run residual generation, forward transform, and quantization
in the encoding stage.

Change-Id: I011bfad3a59a380a869ee552e91dae0394ec492e

vp9/encoder/vp9_onyx_if.c

@@ -834,6 +834,7 @@ void vp9_set_speed_features(VP9_COMP *cpi) {
 
         sf->adaptive_rd_thresh = 2;
         sf->recode_loop = 2;
+        sf->use_lp32x32fdct = 1;
         sf->mode_skip_start = 11;
         sf->intra_y_mode_mask[TX_32X32] = INTRA_DC_H_V;
         sf->intra_y_mode_mask[TX_16X16] = INTRA_DC_H_V;