Fix vcf compare

[joshfactorial]

VCF compare has always been a bit slow and wonky. It should be able to

• read any valid VCF
• compare areas of overlap
• compute statistics related to how close they are

[joshfactorial]

Redoing using a wrapper that calls hap.py, then parses the output from the file to compare accurate read counts, false positives, false negatives, etc.