core/segment.h: sets RATIO_STRAND to only 2

As we have now the e-value check on the KmerSegmenter, there is no need to have
a more stringent value here. Lowering this value enables to have better reports
of unsegmentation causes.

algo/core/segment.h

@@ -16,7 +16,7 @@
 
 #define MIN_D_LENGTH 5          /* If a D-REGION is smaller than this threshold, it is not output */
 
-#define RATIO_STRAND 5          /* The ratio between the affectations in one
+#define RATIO_STRAND 2          /* The ratio between the affectations in one
                                    strand and the other, to safely attribute a
                                    segment to a given strand */