SequenceAlignment.opIndex

enum indelPenalty = 1;
auto alignment = findAlignment("GCATGCT", "GATTACA", indelPenalty);

assert(alignment.score == 4);
assert(alignment.toString ==
    "GCAT-GCT\n" ~
    "| || *|*\n" ~
    "G-ATTACA");

auto partialAlignment = alignment[1 .. 5];

assert(partialAlignment.score == 3);
assert(partialAlignment.toString ==
    "CAT-G\n" ~
    " || *\n" ~
    "-ATTA");