refactor logic to a method for translating the reference
refactor out per library coverage
Added per_library_var_count to VafInterpreter
Add per_library_var_count tests for indels
Slight refactor when calling per_library_coverage
Add per_library_ref_count
calculate_coverage_for_allele now just sums the per_library version
Add calculate_per_library_vaf, which calculate_vaf calls
Make per_lib vaf calculation method. Refactor total vaf method to use it.
Add more test output
Added per_library_vaf to the interpreter.