Remove raw pointers from Sam Readers and Iterators
- correct copy/move constructor/assignment
Remove raw pointers from SamWriter and VariantWriter
- correct copy/move constructors/assignment
Change file pointer type to auto* in readers
Convert writer outputs to unique_ptr
Merge pull request #214 from broadinstitute/jt_raw_pointer_removal

Remove raw pointers from Sam Readers/Iterators and Sam/Variant Writers