enhanced daq processing algorithm to avoid resource starvation between simultaneous DAQs and uploads

changes to sftp utility to allow calculating md5 sum, as well as to be able to use ssh key for authorization

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

added stop-upload command; removed un-needed file stats; improved daq/upload reporting; cleaned up un-needed keys from catalog plugin

reworked reporting for both daqs and uploads; improved ftp utility efficiency; simplified file processing

reworked reporting for both daqs and uploads; improved ftp utility efficiency; simplified file processing

found bug with empty destination directory;prevent checking for upload if plugin does not need to process files

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