Fix upstream and downstream sequence of sequence-info and tweak frameshift process

[nokara26]

I fixed the sequence-info and frameshift alt sequence because error occurred when gene is transcribed from reverse strand and variant includes stop codon and upstream sequence from cds.

I found upstream and downstream sequence is not corrected when deletion is extended to outside of cds.
So I fix upstream sequence from cds-start and downstream sequence from cds-end and tweak frameshift process.

I executed lein run and lein run :slow and I confirmed all tests are passed.

[codecov]

Codecov Report

Merging #80 (7b0f275) into master (493bb81) will increase coverage by 0.66%.
The diff coverage is 52.94%.

@@            Coverage Diff             @@
##           master      #80      +/-   ##
==========================================
+ Coverage   45.66%   46.32%   +0.66%     
==========================================
  Files          16       16              
  Lines        2006     2055      +49     
  Branches       65       68       +3     
==========================================
+ Hits          916      952      +36     
- Misses       1025     1035      +10     
- Partials       65       68       +3     

Files	Coverage Δ
src/varity/vcf_to_hgvs/protein.clj	33.81% <52.94%> (+5.36%)	⬆️

[nokara26]

Close this issue because I created new issue about this problem.
#81