broadinstitute/gamgee — pull request #124 by droazen (2014-07-16 18:04:33+00:00)
Title: When deep copying Sam/Variant records, do not also deep copy the header

Deep copying the headers every time a record is copied is wasteful and
unnecessary, given that headers are immutable (with the single exception
of VariantHeader::advanced_merge_header(), which should be moved to a
builder)