Drop BLAST+6 and replace with docs and constants

[vaastav]

This is a much much cleaner for generating the BLAST+6 files. You should go ahead with the merge once the checks pass.

[codecov-io]

Codecov Report

Merging #76 into master will increase coverage by 6.55%. The diff coverage is 100%.

@@            Coverage Diff             @@
##           master      #76      +/-   ##
==========================================
+ Coverage   92.27%   98.83%   +6.55%     
==========================================
  Files           5        5              
  Lines         233      171      -62     
  Branches       36       30       -6     
==========================================
- Hits          215      169      -46     
+ Misses         16        0      -16     
  Partials        2        2

[mbhall88]

Nice!