Fix bitvec_num_words_for_bits for less than a word bits
Fix bitvec_num_words_for_bits for less than a word bits

timvdm/Helium,timvdm/Helium,ahasgw/Helium,timvdm/Helium,ahasgw/Helium,timvdm/Helium,ahasgw/Helium