Jointly coding gain/theta/noref on P-frames

video1-short results:
non-robust:
           RATE (%)  DSNR (dB)
    PSNR -0.35052  0.01787
 PSNRHVS -0.40397  0.03273
    SSIM -0.38161  0.01849
FASTSSIM -0.36484  0.02334

robust:
           RATE (%)  DSNR (dB)
    PSNR -1.85044  0.10021
 PSNRHVS -2.16841  0.17816
    SSIM -1.93902  0.09961
FASTSSIM -1.98467  0.13023
Change ordering of CfL flip flag so that it's encoder just after use.

This will allow us to do joint noref/gain/theta coding on keyframes
Using joint noref/gain/theta coding for keyframes too

subset1 results:
           RATE (%) DSNR (dB)
    PSNR -0.481762 0.0305003
 PSNRHVS -0.743942 0.0449025
    SSIM -0.56423 0.0312397
FASTSSIM -1.25077 0.0409497