Updates clirr config to ignore on purpose broken functionality
Fixes PhysicalLogFileInformation to provide timestamp info

There is a cyclic dependency present between PhysicalLogFileInformation
 and PhysicalLogFile. PLFI requires a reader to read transactions from
 the log to extract timestamp information while PLF needs PLFI to have
 a working LogPruneStrategy. This must be broken somehow, probably by
 having a timestamp field in the header of the log files. But for
 now we'll have to do by having an SPI satisfy PLFI's needs.

Also adds some basic tests for ThresholdPruneStrategy.