remove max slice number constraint
Add RELEASES file
Merge pull request #890 from ethanhugg/release_notes

Add RELEASES file
Merge pull request #886 from ganyangbbl/rm_slicenum_constraint

remove max slice number constraint
  remove redundant code for mb qp calculation
Merge pull request #895 from ruil2/enc_rc_1

  remove redundant code for mb qp calculation