encode: move allocations out of encode_create
Fix typo in od_mc_predict8

Results on video-1-short:
          RATE (%)  DSNR (dB)
    PSNR  0.05477  -0.00294
 PSNRHVS -0.27886   0.02215
    SSIM -0.22127   0.01067
FASTSSIM -0.13975   0.00859
Remove incorrect assertion: level 2 MVs outside the frame can be valid
state: cleanup on allocation failure
internal: add OD_UNLIKELY macro