Added data object query clause to limit returned results to the newest
added replicate. This avoids old copies that have been superseded.

Renamed log -> logmsg to avoid name clash.
Added the iRODS replicate number to timestamp query results for data objects.

Changed list_timestamps to report timestamps for all replicates.

Limited timestamp reporting to the lowest numbered extant replicate.
Tidied up includes.
Bug fix for unbuffered operation
Merge pull request #62 from keithj/devel

Bug fixes for behaviour on replicates and old copies of data objects.