update filters; add pileup element fields and filters
add tests for loading/filtering reads; test mdtag conversion; fix mdtag MD:Z:0
Merge pull request #127 from hammerlab/pileup-data

update filters; add pileup element fields and filters
Merge pull request #128 from hammerlab/mdtagissue

Add tests for loading/filtering reads; test mdtag conversion; fix mdtag ...
start on window based structural variant caller