version 2.0_beta where PE reads are processed separately and selected or removed from the cms if at least one of the PE has a median coverage below threshold.

did new implementation for using only the max(k-mer value, reverse complement value) in the CMS; updates unit tests accordingly.

bugfix : now increment the counter for only the biggest hash value obtained for a k-mer and its reverse complement. Before, I incemented both counters and it is not what we want.

changed srp structure a little it; replace long by int for a1 and a2. Aim is to be more memory efficient.

first working implementation of Count min sketch component with a bit shifting hash function. TODO find more effective hash functions.