Changes to default values for Filters, the Statistic saving process and a FrequencyFilter fix

- changed default path for LTM export to /tmp/ltm/MemoryExport
- changed trigger for when statistics are saved
	- saving directly after a recording was stopped
	- only save statistics if a valid time of start for the recording was detected
	- do not save empty statistics files
	- if no snapshots were accepted or rejected no filter statistics are added and if that is the case for all filters an exception is thrown (and catched which then leads to an empty statistic)
- changed namespace of MemoryBase.cpp to match MemoryBase.h
- FrequencyFilter fix looks at each entity seperately when comparing lastStored times (should solve issues with multiple provider/core segments in one memory)
	- needs to be tested