add support for writing BCF
build up bcf record directly rather then via vcf_parse
match style for variable names
add -writeVcfGz and condense -writeVcf etc usage messages
update bcf alleles
remove some strange local file that got committed
try to match RD coding style
Merge branch 'master' of github.com:richarddurbin/pbwt into feature/writeBcf
Merge pull request #19 from mcshane/feature/writeBcf

support for writing out BCF