Cleaup Near-lossless code.
Cleaup Near-lossless code.

Cleaup Near-lossless code
- Simplified and refactored the code.
- Removed the requirement (TODO) to allocate the buffer of size WxH and work
  with buffer of size 3xW.
- Disabled the Near-lossless prr-processing for small icon images (W < 64 and H < 64).

Change-Id: Id7ee90c90622368d5528de4dd14fd5ead593bb1b

altogother/webm.libwebp,yohunl/libwebp,abwiz0086/webm.libwebp,webmproject/libwebp,zofuthan/libwebp,ttyangf/libwebp,zofuthan/libwebp,jiehu5114/libwebp,iniwf/webm.libwebp,kleopatra999/webm.libwebp,matanbs/webm.libwebp,zofuthan/libwebp,altogother/webm.libwebp,webmproject/libwebp,redengineer/libwebp,rxl194/libwebp,imazen/libwebp,PKRoma/libwebp,gshORTON/webm.libwebp,yohunl/libwebp,gshORTON/webm.libwebp,kalli123/webm.libwebp,Maria1099/webm.libwebp,jacklicn/libwebp,Aexyn/libwebp,ya7lelkom/libwebp,matanbs/webm.libwebp,matanbs/webm.libwebp,Aexyn/libwebp,iniwf/webm.libwebp,PKRoma/libwebp,redengineer/libwebp,rxl194/libwebp,imazen/libwebp,jiehu5114/libwebp,ttyangf/libwebp,ttyangf/libwebp,gshORTON/webm.libwebp,kim42083/webm.libwebp,Suvarna1488/webm.libwebp,jacklicn/libwebp,ericmckean/webm.libwebp,redengineer/libwebp,reimaginemedia/webm.libwebp,PKRoma/libwebp,Acidburn0zzz/webm.libwebp,webmproject/libwebp,ya7lelkom/libwebp,Suvarna1488/webm.libwebp,jiehu5114/libwebp,kalli123/webm.libwebp,Maria1099/webm.libwebp,redengineer/libwebp,Acidburn0zzz/webm.libwebp,rxl194/libwebp,webmproject/libwebp,Maria1099/webm.libwebp,rxl194/libwebp,kleopatra999/webm.libwebp,Maria1099/webm.libwebp,gshORTON/webm.libwebp,abwiz0086/webm.libwebp,reimaginemedia/webm.libwebp,abwiz0086/webm.libwebp,jacklicn/libwebp,Acidburn0zzz/webm.libwebp,ericmckean/webm.libwebp,PKRoma/libwebp,ya7lelkom/libwebp,reimaginemedia/webm.libwebp,kim42083/webm.libwebp,zofuthan/libwebp,jacklicn/libwebp,zofuthan/libwebp,kalli123/webm.libwebp,redengineer/libwebp,iniwf/webm.libwebp,PKRoma/libwebp,imazen/libwebp,Aexyn/libwebp,Suvarna1488/webm.libwebp,gshORTON/webm.libwebp,jacklicn/libwebp,altogother/webm.libwebp,kleopatra999/webm.libwebp,matanbs/webm.libwebp,iniwf/webm.libwebp,webmproject/libwebp,Aexyn/libwebp,yohunl/libwebp,imazen/libwebp,Acidburn0zzz/webm.libwebp,yohunl/libwebp,ttyangf/libwebp,ericmckean/webm.libwebp,iniwf/webm.libwebp,abwiz0086/webm.libwebp,Acidburn0zzz/webm.libwebp,Suvarna1488/webm.libwebp,matanbs/webm.libwebp,kleopatra999/webm.libwebp,ericmckean/webm.libwebp,kim42083/webm.libwebp,jiehu5114/libwebp,reimaginemedia/webm.libwebp,altogother/webm.libwebp,imazen/libwebp,altogother/webm.libwebp,Suvarna1488/webm.libwebp,reimaginemedia/webm.libwebp,ttyangf/libwebp,jiehu5114/libwebp,kalli123/webm.libwebp,kim42083/webm.libwebp,ericmckean/webm.libwebp,PKRoma/libwebp,kim42083/webm.libwebp,kleopatra999/webm.libwebp,Maria1099/webm.libwebp,ya7lelkom/libwebp,yohunl/libwebp,kalli123/webm.libwebp,ya7lelkom/libwebp,abwiz0086/webm.libwebp,rxl194/libwebp,Aexyn/libwebp