Yf add getters to vcb

[yfarjoun]

Description

Please explain the changes you made here. Explain the motivation for making this change. What existing problem does the pull request solve?

Checklist

• [ ] Code compiles correctly
• [ ] New tests covering changes and new functionality
• [ ] All tests passing
• [ ] Extended the README / documentation, if necessary
• [ ] Is not backward compatible (breaks binary or source compatibility)

[yfarjoun]

@lbergelson can you review please?

[codecov-io]

Codecov Report

Merging #1247 into master will increase coverage by 0.131%. The diff coverage is 6.667%.

@@               Coverage Diff               @@
##              master     #1247       +/-   ##
===============================================
+ Coverage     69.407%   69.538%   +0.131%     
- Complexity      8157      8278      +121     
===============================================
  Files            548       548               
  Lines          32691     33153      +462     
  Branches        5521      5643      +122     
===============================================
+ Hits           22690     23054      +364     
- Misses          7783      7852       +69     
- Partials        2218      2247       +29

Impacted Files	Coverage Δ	Complexity Δ
.../variant/variantcontext/VariantContextBuilder.java	72.222% <6.667%> (-7.167%)	35 <3> (ø)
src/main/java/htsjdk/samtools/SamStreams.java	72.165% <0%> (-0.143%)	20% <0%> (+1%)
src/main/java/htsjdk/variant/bcf2/BCF2Codec.java	79.435% <0%> (+3.245%)	44% <0%> (+11%)	:arrow_up:
...samtools/util/AsyncBlockCompressedInputStream.java	76% <0%> (+4%)	13% <0%> (+1%)	:arrow_up:
...c/main/java/htsjdk/samtools/util/IntervalList.java	72.11% <0%> (+4.654%)	108% <0%> (+37%)	:arrow_up:
src/main/java/htsjdk/samtools/util/IOUtil.java	62.835% <0%> (+5.692%)	186% <0%> (+71%)	:arrow_up: