Implemented No Op API that is used when crypto is not present

[codecov-io]

Codecov Report

Merging #61 into master will decrease coverage by 0.15%. The diff coverage is 84.84%.

@@            Coverage Diff             @@
##           master      #61      +/-   ##
==========================================
- Coverage   91.54%   91.38%   -0.16%     
==========================================
  Files          34       34              
  Lines        1454     1486      +32     
  Branches      192      198       +6     
==========================================
+ Hits         1331     1358      +27     
- Misses        123      128       +5

Impacted Files	Coverage Δ
ts/protocol/errors.ts	93.33% <100%> (+0.31%)	:arrow_up:
ts/api/api.ts	90.9% <82.75%> (-1.21%)	:arrow_down:

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[TMSCH]

@tikurahul I added unit tests, PTAL.

[TMSCH]

Thanks Rahul!