Version 2.2.4

[Nathan Clement]

I've just updated the latest version (2.2.4): http://dna.cs.byu.edu/gnumap/gnumap-2.2.4.tgz

Notable updates:

* Minor changes to --up_strand and --down_strand functionality
* Added flag --print_all_sam to print all SAM matches instead of only the top matching hit.
* Added extra flag to SAM file XP:f:<POST_PROB> that stores a floating point value for the posterior probability of each match. Traditionally, the MAPQ location is used, but significant round-off error prevents this from being realistic.