making Ns encode as 0000 instead of 1111 because they are treated as mismatches in abismal

Author: guilhermesena1

dna_four_bit.cpp

@@ -65,14 +65,14 @@ char dna_four_bit_decoding[] = {
 */
 uint8_t dna_four_bit_encoding[] = {
 /*first*/                                                               /*last*/
-/*  0*/ 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,  /* 15*/
-/* 16*/ 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,  /* 31*/
-/* 32*/ 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,  /* 47*/
-/* 48*/ 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,  /* 63*/
-/* 64*/ 15,  1, 14,  2, 13, 15, 15,  4, 11, 15, 15, 12, 15,  3, 15, 15,  /* 79*/
-/* 80*/ 15, 15,  5,  6,  8, 15,  7,  9, 15, 10,  0, 15, 15, 15, 15, 15,  /* 95*/
-/* 96*/ 15,  1, 14,  2, 13, 15, 15,  4, 11, 15, 15, 12, 15,  3, 15, 15,  /*111*/
-/*112*/ 15, 15,  5,  6,  8, 15,  7,  9, 15, 10,  0, 15, 15, 15, 15, 15   /*127*/
+/*  0*/ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /* 0*/
+/* 16*/ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /* 31*/
+/* 32*/ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /* 47*/
+/* 48*/ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /* 63*/
+/* 64*/ 0,  1, 14,  2, 13, 0, 0,  4, 11, 0, 0, 12, 0,  3, 0, 0,  /* 79*/
+/* 80*/ 0, 0,  5,  6,  8, 0,  7,  9, 0, 10,  0, 0, 0, 0, 0, 0,  /* 95*/
+/* 96*/ 0,  1, 14,  2, 13, 0, 0,  4, 11, 0, 0, 12, 0,  3, 0, 0,  /*111*/
+/*112*/ 0, 0,  5,  6,  8, 0,  7,  9, 0, 10,  0, 0, 0, 0, 0, 0   /*127*/
 };
 //       .   A   B   C   D   .   .   G   H   .   .   K   .   M   N   .
 //       .   .   R   S   T   .   V   W   .   Y   Z