modify/update dig-extract/dig/tool/db2url/db2url to compute timestamp
works but writes json to tsv file; with debug output
remove debug printing; dump to source-specific json file
Merge branch 'master' of https://github.com/usc-isi-i2/dig-prep
use importtime*1000, not modtime
add helper functions
Merge branch 'master' of github.com:usc-isi-i2/dig-prep