Refactoring Error Logging Inconsistencies in MdTag.scala

[joonkang-git]

After review there were several inconsistencies found in the file MdTag.scala in terms of error logging.

throw new IllegalArgumentException(s"MdTag $mdTagInput does not start with a digit")

case _ => throw new IllegalStateException("Could not find deleted base at cigar offset " + i)

These are included in the code without a clear pattern to their usage. In addition the error messages associated are inconsistent in detail.