VCF Overhaul

[charlesgregory]

Lots of changes went into this.

fixes #96.

New Features:

• HeaderRecord wrapper struct for getting VCFHeader records in a structured format along with getters and setters and VCFHeader can now accept this type to add to a header.
• ability to remove header lines removeHeaderLines.
• Moved functions from VCFReader to VCFHeader as appropriate.
• New InfoField and FormatField wrapper structs to get and transform VCF format and info data into D types (data is copied).
• New functions (getInfos and getFormats) to return a hashmap of all info and format data using new wrapper structs.
• New function to remove info fields removeInfo.
• New enum replacements for htslib BCF* enums.
• lots of new unittests

Though I did introduce a lot of new features, I have tried to leave old functionality behind. (Though with the reorganization and the enums, the API will change for most of dhtslib.vcf).

Fixes:

• Fixes to addFormat and addInfo functions.
• Fixes for VCFHeader functions
• VCFReader now obeys Phobos Range rules, fixes #69
• Unittest coverage for all dhtslib.vcf modules is >= 92%, fixes #94

Concerns:

1. We sometimes report errors through hts_log and have the function return, sometimes we report errors through hts_log and have the function throw an exception, or sometimes we just throw an exception. We should decide formally on how this should be done across the whole package, #99 probably relevant.
2. Naming in general. I am not sold on my naming of the new enums, I just wanted them to be more informative than the htslib enums.
3. Could use more asserts and checks

[codecov-commenter]

Codecov Report

Merging #105 (da10a93) into develop (b4e5e01) will increase coverage by 3.41%. The diff coverage is 91.29%.

:exclamation: Current head da10a93 differs from pull request most recent head 1768e09. Consider uploading reports for the commit 1768e09 to get more accurate results

@@             Coverage Diff             @@
##           develop     #105      +/-   ##
===========================================
+ Coverage    80.40%   83.82%   +3.41%     
===========================================
  Files           40       40              
  Lines         2822     3424     +602     
===========================================
+ Hits          2269     2870     +601     
- Misses         553      554       +1     

Impacted Files	Coverage Δ
source/dhtslib/sam/record.d	76.61% <79.59%> (-4.64%)	:arrow_down:
source/dhtslib/sam/tagvalue.d	95.90% <83.33%> (-0.63%)	:arrow_down:
source/dhtslib/vcf/record.d	91.27% <87.07%> (+0.05%)	:arrow_up:
source/dhtslib/sam/reader.d	87.60% <94.44%> (+2.96%)	:arrow_up:
source/dhtslib/vcf/header.d	95.58% <95.40%> (+70.58%)	:arrow_up:
source/dhtslib/vcf/reader.d	96.92% <96.92%> (+2.05%)	:arrow_up:
source/dhtslib/sam/cigar.d	89.76% <100.00%> (+0.33%)	:arrow_up:
source/dhtslib/vcf/writer.d	100.00% <100.00%> (+47.54%)	:arrow_up:
source/htslib/sam.d	52.17% <100.00%> (+2.17%)	:arrow_up:
... and 4 more

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[charlesgregory]

Alright I added several changes to the enums. They now refer directly to the htslib BCF_* enums. I expanded some of the enum names to make them more self-explanatory. I made a function for calling bcf_unpack to standardize it for all functions along with unittests to confirm it works.

I also changed the default MAX_UNPACK value to UnpackLevels.None as this should help performance by default and help us better catch bugs where we have not correctly unpacked data before using it. You may disagree with this sentiment. Let me know.

Still todo:

• Decide on no-copy vs copy for InfoField and FormatField
• Convert integration tests to actual unittests
• move integration tests to tests folder
• dfmt

[charlesgregory]

I think this should be ready to go.