accumulate dec stat
fix crash issue of sliceskip and inf-loop in fmo
Merge pull request #1589 from huili2/fix_fmo_sliceskip

fix crash issue of sliceskip and inf-loop in fmo
Merge pull request #1588 from huili2/dec_stat_accumulate

accumulate dec stat
fix grey picture when resolution is the same
Merge pull request #1592 from dongzha/FixGreyPic

fix grey picture when resolution is the same
Switch to use stable branch of gmp-api
Merge pull request #1593 from ethanhugg/gmpapiversion

Switch to use stable branch of gmp-api
Rate control refine to fit MAX bitrate requirement
   1. should not set WELS_LOG_ERROR level in encoder initilization.
   2.fix UT bug
change info level as default level
Merge pull request #1595 from ruil2/update_2

should not set WELS_LOG_ERROR level in encoder initilization.
Merge pull request #1594 from lyao2/RC_maxBr_commit5

Rate control refine to fit MAX bitrate requirement