introduce timer for directory processing; fix for updating file permissions when directory processing is used

modifications to eliminate processing of hidden files and of unchanged files that were processed already; checksum is now done by default

added user interfaces and utilities that enable experiment data download from machines that have ssh access to the storage host

added DB and DS web service interfaces for deleting user experiment role; added new delete-user-experiment-role command

introduced interface for notifying ds service to update experiment users; fix bug in linux experiment utility

add file processing interfaces; rename storage manager to experiment manager; add ability to manage groups/file permissions