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

fixed few issues found while testing gridftp plugin and file observer; made observer more generic by shifting some functionality to agent