BAM parsing optimization

[cmdcolin]

This addresses #969

The performance is about 3x as fast, measured here

https://jsperf.com/md-parsing

This does so by adjusting CIGAR parsing and MD usage of the CIGAR

[codecov]

Codecov Report

Merging #993 into master will increase coverage by 0.03%.
The diff coverage is 85.00%.

@@            Coverage Diff             @@
##           master     #993      +/-   ##
==========================================
+ Coverage   58.42%   58.45%   +0.03%     
==========================================
  Files         386      387       +1     
  Lines       15849    15884      +35     
  Branches     3577     3581       +4     
==========================================
+ Hits         9259     9285      +26     
- Misses       6294     6304      +10     
+ Partials      296      295       -1     

Impacted Files	Coverage Δ
...es/alignments/src/PileupRenderer/PileupRenderer.ts	89.72% <ø> (ø)
packages/alignments/src/PileupRenderer/sortUtil.ts	41.46% <ø> (ø)
...lignments/src/BamAdapter/BamSlightlyLazyFeature.ts	64.70% <62.50%> (-11.32%)	⬇️
...ckages/alignments/src/BamAdapter/MismatchParser.ts	86.60% <86.60%> (ø)
packages/core/util/index.ts	81.59% <0.00%> (+0.34%)	⬆️

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[rbuels]

niiice