changes to sftp utility to allow calculating md5 sum, as well as to be able to use ssh key for authorization
reworked catalogging to use collection on a per experiment basis; removed generic apis for retrieving files
added new polling observer agent; enhanced upload functionality to avoid resource starvation with simultaneous daqs and uploads; resolved issue with starting uploads with large number of files in the specified directory
introduce timer for directory processing; fix for updating file permissions when directory processing is used
