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 and update numLtrp accordingly 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.