Moved BamAlignmentSupportData into BamAlignment data type. This continues the read...

Moved BamAlignmentSupportData into BamAlignment data type. This continues the read/write speedup mentioned in prior commits, but removes the need for clients to manage this additional auxilary data object. The 'BamAlignment lite' is accessed by calling BamReader::GetNextAlignmentCore() and written by BamWriter::SaveAlignment() which checks to see how much parsing & packing is needed before writing.