Fix maf2maf by using vcf2maf with inhibit-vep arg

Use DP4 for allele counts when AD is missing

Use buffer-size to limit CLI args for samtools/tabix

Fix tabs for empty MAF columns before newline

Fix: VCFs need semicolon delim FILTER data, and header lines

Support un-normalized input VCFs

Tighter default max-filter-ac of 10

Gracefully handle empty VCFs

Ability to liftOver variants before VEP

Fix ref matching for long indels