Integrate space-efficient SA algorithm.

This integerates the algorithm proposed in "Space-Efficient Construction of the Burrows-Wheeler Transform" SPIRE2013. Instead of computing the BWT, the SA is computed. Its limited to Byte-Alphabet inputs and does not yet contain the described optimization described in the paper for very small alphabets (like dna-data). However, now the suffix array can be constructed with less space, usually less than 1.5n Bytes, see included example.
Note that isn't so fast than divsufsort.