Add new 4-point Type-II DCT implementation.
Add new 4-point Type-II DCT implementation.

subset-1:

master@2017-11-27T19:24:03.517Z -> new_dct4@2017-11-27T20:52:07.119Z

   PSNR | PSNR Cb | PSNR Cr | PSNR HVS |   SSIM | MS SSIM | CIEDE 2000
-0.0113 |  0.0459 |  0.1285 |   0.0085 | 0.0005 |  0.0093 |     0.0352

Change-Id: I0a76037ea2a08071ca9c4013979cca3ee3efe55c

GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom