Fix #499: parsing of rpls_poc_lsb_lt and slice_pos_lsb_lt

- rpls_poc_lsb_lt shall be parsed when !ltrp_in_slice_header_flag
- When ltrp_in_slice_header_flag = 0, the value of st_ref_pic_flag are
needed to parse slice_poc_lsb_lt. Add the update RefPicIdentifier in
this case.
- Using two separate index ii and j might cause the overwriting of short term
information by long term one as the RefPicIdentifier array are common.
Remove j.