Supports parallel recording of two LTMs with different filters now.

One WM can be connected to two different LTMs to see the effects of different filters on exactly the same WM.
Second LTM will be saved at /tmp/MemoryExport2.

Added a second ltm::Memory to the MemoryToIceAdapter, added storage function to commit.
Changed the FrequencyFilter to be more similar to the ImportanceFilter. Careful: accepting to many elements leads to loss of entity instances because BufferdMemoryMixin is not fast enough.
Fixed ImportanceFilter to any one of the instances triggers acceptance and not only the last one.
Added secondLTM to the iceAdapter, set MemoryIDs and loaded propertyDefinitions in Plugin.cpp.
To make sure statistic files are written, added preOnExitComponent and statistics_saved flag. Possibility to save information for both LTMs/filters.