-- Disturbingly, fixing this bug doesn't actually cause an test failures.
-- Wrote a new QCRefWalker to actually check in detail that the reference bases coming into the RefWalker are all correct when comparing against a clean uncached load of the contig bases directly.
-- However, I cannot run this tool due to some kind of weird BAM error -- sending this on to Matt
non-static to avoid problems when multiple references are used within the same
thread (eg., during integration tests). This should kill the intermittent
IndelRealignerIntegrationTest failures.