Fixed several bugs in the BLISS signature generation/verification step.

Fixed several bugs in the BLISS signature generation/verification step.

The c_indices derived from the SHA-512 random oracle consist of
nine bits (0..511). The leftmost 8 bits of each index are taken
on an octet-by-octet basis from the 56 leftmost octets of the
SHA-512 hash. The 9th bit needed for the LSB is taken from the
extra_bits 64 bit unsigned integer which consists of the 8 rightmost
octets of the SHA-512 hash (in network order). If more than 56
indices must be derived then additional rounds of the random oracle
are executed until all kappa c_indices have been determined.

The bug fix shifts the extra_bits value by one bit in each loop
iteration so that the LSB of each index is random. Also iterate
through the hash array using the loop variable j not the c_indices
variable i.