Allow "Flag" values in the INFO field

"Flag" type INFO annotations do not have the canonical key=value
format as other annotations. The ouput.yaml file can be adapted
for a flag type annotation:

SegDupFlag:
	vcf-name: INFO.SegDup
	flag: "True"

Where the "flag" value is used to fill out the tab-delimited file.
The default flag value is "True".