model.py: class Record: merge function added, so that vcf records can get merged with records coming from different callers
model.py: class Record: function merge dealing with multiple alternative alleles. class Call: creation of function append
model.py: class Record: function merge dealing with multiple alternative alleles. class Call: creation of function get_aaf and append_aaf
model.py: Call class: aaf and depth properties created
model.py: Call class: aaf and depth properties created
model.py: Call class: aaf and depth properties created
model.py: Call class: aaf and depth properties created
model.py: Call class: aaf and depth properties created
model.py: Record class: merge function should only added fields from other callers if variants are of same type (snps, indels)
model.py: Record class: more logic implemented in merge function