Implemented deplete_blastn_prep.
Merge pull request #32 from broadinstitute/irwin-taxon_filter_interfaces

Irwin taxon filter interfaces
Merge branches 'irwin-taxon_filter' and 'master' of github.com:broadinstitute/viral-ngs
Merge branch 'master' into irwin-taxon_filter
Implemented deplete_blastn and fix_mate_pair_info without testing.
Created TestCaseWithTmp and derived from it in all tests that setUp and tearDown tmpDir.
Debugged and added test for deplete_blastn.