refactor release management command to work incrementally
change sitemap_indexed column from boolean to datetime
split release and update-sitemap into two commands: In progress
code to handle release command input tsv
set sitemap_indexed on batches and titles that have been indexed
Release command: Changed the key to look for in bag-info.txt
b -> batch variable rename
fixed batch selection query
Merge pull request #74 from LibraryOfCongress/_release_command_rework

 release command rework